• Title/Summary/Keyword: mobile emission

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Adjacent Interference Analysis between M-WiMAX OFDMA/TDD and WCDMA FDD System in the 2.6 GHz Band Part I : Adjacent Interference Analysis in SISO System (2.6 GHz 대역에서 M-WiMAX OFDMA/TDD 시스템과 WCDMA FDD 시스템간의 상호 간섭 분석 Part I : SISO 시스템에서의 상호 간섭 분석)

  • Ko, Sang-Jun;Wang, Yu-Peng;Chang, Kyung-Hi
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.6A
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    • pp.573-587
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    • 2007
  • In this paper, we analyze the adjacent interference between WCDMA and M-WiMAX systems in the 2.6GHz Band under the SISO (Single Input Single Output) configuration. The interference scenarios are characterized into 8 scenarios with different victim and interfering links. Among the 8 scenarios, we find that the most performance loss is observed in the scenarios of victim uplink suffering interference from downlink in both systems. Besides, guard band is applied to mitigate the adjacent interference in all the scenarios. Especially, we reveal that M-WiMAX system is much more sensitive to adjacent interference than WCDMA system due to the lower transmission power. In this paper, we consider the worst interference environment, where interferers always transmit with the maximum power, a loose spectrum mask is adapted, and no additional channel fitters are equipped in both systems.

A Study on Experiment of Transmission Power Assignment for Indoor TVWS Wireless Communication System (실내 TVWS 무선통신을 위한 송신 전력 설정 실험에 관한 연구)

  • Yun, Deok-Won;Chang, Hyung-Min;Lee, Won-Cheol
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38B no.10
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    • pp.851-860
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    • 2013
  • To overcome a scarcity of radio resources to mobile broadband service, the usage of TV white space gains much attraction around the world. This paper carries out an interference analysis either by performing realistic experiments or by executing statistical Monte-Carlo simulation to exploit interference probability. The results obtained from experiments are compared to those from simulations in order to clarify the coexistence of utilization of TV band devices (TVBD) in indoor circumstances. Along the execution of our experiment in the presence of DTV receiver, we apply to a variety of transmission parameters proposed in FCC for TVBD. According to experimental and simulation works, the allowable transmission powers of TVBD systems are exploited for the plausible which are coexist on the first as well as the second adjacent frequency bands. Throughout results, it can conclude that TVBD systems can be coexisted via achieving proper transmission powers depending on the locations of themselves without showing harmful interference to DTV reception.

Spatial-temporal variations in surface ozone concentrations in Busan metropolitan area (부산지역 오존농도의 시·공간 분포 변화)

  • Kang, Yoon-Hee;Kim, Yoo-Keun;Hwang, Mi-Kyeong;Jeong, Ju-Hee;Kim, Hyunsu;Kang, Min-Seong
    • Journal of Environmental Science International
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    • v.28 no.2
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    • pp.169-182
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    • 2019
  • Temporal and spatial variations in surface ozone concentrations in Busan were investigated by using observation data from urban air quality sites during 2001-2016. The annual ozone concentrations showed a significant increasing trend of $+0.40ppb\;yr^{-1}$ in this period, with a more rapid increase of $+0.81ppb\;yr-1$ since 2010. For the monthly analysis, the increase in ozone concentration was the greatest in August ($+0.68ppb\;yr-1$). These ozone trends were due mainly to rising temperature ($+0.05^{\circ}C\;yr^{-1}$) and weak decreasing precipitation ($-6.42mm\;yr^{-1}$). However, the extreme weather events (heat wave, localized heavy rain, etc.) lead to an increase in short-term variability of ozone since 2010. The relatively low ozone concentrations in the downtown area were caused by high NOx emissions from mobile sources. The increases in ozone concentrations were observed at most of the air quality monitoring sites due to the reductions in anthropogenic emissions of NOx during 2001-2015. However, in the southern coastal area, lower rates of increase in ozone concentrations were observed by $-0.10{\sim}0.25ppb\;yr^{-1}$ due to the significant NOx emitted by ships in the Busan port and Busan new port.

Determination of benzo(a)pyrene in olive oils (올리브유 중 벤조피렌 분석)

  • Hu, Soojung;Woo, Gun-Jo;Choi, Dongmi
    • Analytical Science and Technology
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    • v.20 no.2
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    • pp.170-175
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    • 2007
  • To determine levels of benzopyrene in olive oils, a selective analytical method of HPLC/FLD has been applied. After removing fat in food samples with hexane, it was extracted in aqueous N,N-DMF solution, cleaned-up on florisil SPE cartridge and analyzed by the instrumental analysis. The mobile phase was a mixture of acetonitrile and water in 8:2 by the isocratic elution and the excitation wavelength of fluorescence detector was 294 nm and emission wavelength of it was 404 nm. The average recovery was about 95 % and the limit of quantitation was $0.9{\mu}g/kg$. The levels of benzopyrene in the selected olive oil samples were ranged from not detected to $1.9{\mu}g/kg$, however, they were under $2.0{\mu}g/kg$, the maximum level of benzopyrene in olive oil which was established in the food code.

Implementation of Segway Using Pressure Sensors (압력센서를 이용한 세그웨이 개발)

  • Jo, Sung-Chan;Kang, Su-Min;Huh, Kyung-Moo;Joo, Young-Bok
    • Journal of the Institute of Electronics and Information Engineers
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    • v.50 no.1
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    • pp.285-290
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    • 2013
  • As well as the advanced development of modern society, and the environmental problems caused by the use of fossil fuels is emerging. So do not reap the performance level of the car to be able to replace existing fossil fuel and low-emission energy and technology development are continually strives. Therefore, this study aims to present the direction of the new interface 21st century Mobile Auto Electric Segway technology in the field of security and disadvantages based. The Segway is a problem because the control itself skewed by certain slope where the slope in the wrong adjustment tipping. In this study, the year saw the introduction of two pressure sensors(Load cell) used to solve these drawbacks, according to the ratio of the weight control methods. In addition, the ramps operate in a straightforward, using an acceleration sensor and a gyro sensor in order to compensate for the slope value in free control method to study looked. Measured by calculating the value of the occupant's weight and according to the inclination of the pressure sensor pressure sensing experiment results this year, we can see that the control variable for the change in body weight is greater than the inclination. Segway is also easy to control, and the stability of the ramps, etc. As a result, created using a pressure sensor.

Effect of Target Material and the Neutron Spectrum on Nuclear Transmutation of 99Tc and 129I in Nuclear Reactors (표적물질 및 중성자 스펙트럼이 99Tc과 129I의 원자로 내부 핵변환에 미치는 영향)

  • Kang, Seung-gu;Lee, Hyun-chul
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.16 no.2
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    • pp.195-202
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    • 2018
  • As a rule, geological disposal is considered a safe method for final disposal of high-level radioactive waste. However, some long-lived fission products like $^{99}Tc$ and $^{129}I$ contained in spent nuclear fuel are highly mobile as less sorbing anionic species in the subsurface environment and can mainly cause exposure dose to the ecosystem by emission of beta rays in the hundreds of keV range. Therefore, if these two nuclides can be separated and converted with high efficiency into radioactively unharmful nuclides, this would have a positive effect on disposal safety. One candidate method is to transmute these two nuclides in nuclear reactors into short-lived nuclides or into stable nuclides. For this purpose, it is necessary to evaluate which reactor type is more efficient in burning these two nuclides. In this study, the simulation results of nuclear transmutation of $^{99}Tc$ and $^{129}I$ in light water reactor (PWR), heavy water reactor (CANDU) and fast neutron reactor (SFR, MET-1000) are compared and discussed.

Health and Environmental Risk Assessment of Pollutants in Pohang (포항지역 오염물질 보건.환경 위해성 평가 -미세먼지의 발생특성 및 농도분포를 중심으로-)

  • Jung, Jong-Hyeon;Choi, Won-Joon;Leem, Heon-Ho;Shon, Byung-Hyun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.7
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    • pp.2719-2726
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    • 2010
  • The purpose of this study was to investigate the scientific basic grounds for the assessment of health and environmental diseases resulting from air pollutants in Pohang. For this study, we investigated pollutants, weather characteristics and concentration distribution of fine particles ($PM_10$) yearly and each season, using data from Air Quality Monitoring Stations. The properties of concentration distribution and seasonal fluctuation of $PM_10$ were studied qualitatively and quantitatively using CALPUFF, air dispersion model. The average concentration of $PM_10$ for each season was spring($75.7{\mu}g/m^3$)>summer($56.8{\mu}g/m^3$)>winter($53.6{\mu}g/m^3$)>fall( $52.7{\mu}g/m^3$). In the case of spring, high concentrations appear due to the Asian dust frequently occurring. The contributions of $PM_10$ classified by the types of pollution source in Pohang were point source 62%>mobile source 33%>area source 5%. An important point is that 97% of emissions were produced from the iron manufacture in steel industry. Therefore, it is necessary to control the emission sources of pollutants and to construct an observation system at Pohang steel industrial complex from now on. It’s time to control the risk factors for health and environmental disease to protect the health of resident in Pohang and its neighboring areas.

Adsorption of Mn on iron minerals and calcium compounds to reduce Mn(II) toxicity (2가 망간의 독성 저감을 위해 철산화물과 칼슘화합물을 이용한 망간 흡착)

  • Hyo Kyung Jee;Jin Hee Park
    • Journal of Applied Biological Chemistry
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    • v.65 no.4
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    • pp.457-462
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    • 2022
  • Manganese (Mn) exists in various oxidation states and Mn(II) is the most mobile species of Mn, which is toxic to plants and limits their growth. Therefore, the purpose of this study was to reduce Mn toxicity by immobilizing Mn using various adsorbents including iron oxides and calcium compounds. Ferrihydrite, schwertmannite, goethite were synthesized, which was confirmed by X-ray diffraction. Hematite was purchased and used as Mn adsorbent. Calcium compounds such as CaNO3, CaSO4, and CaCO3 were used to increase pH and oxidize Mn. For Mn adsorption, Mn(II) solution was reacted with four iron oxides, CaNO3, CaSO4, and CaCO3 for 24 hours, filtered, and the remaining Mn concentrations in the solution were analyzed by inductively coupled plasma optical emission spectroscopy. The adsorption rate and adsorption isotherm were calculated. Among iron oxides, the adsorption rate was highest for hematite followed by ferrihyrite, but goethite and schwertmannite did not adsorb Mn. In the case of calcium compounds, the adsorption rate was high in the order of CaCO3>CaNO3>CaSO4. In conclusion, treatment of CaCO3 was the most effective in reducing Mn toxicity by increasing pH.

The Partitioning Characteristics of Heavy Metals in Soils of Ulsan by Sequential Extraction Procedures (단계별추출법에 의한 울산지역 토양 중의 중금속 Partitioning 특성연구)

  • Lee, Byeong-Kyu;Koh, Il-Ha;Kim, Haeng-Ah
    • Journal of Korean Society of Environmental Engineers
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    • v.27 no.1
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    • pp.25-35
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    • 2005
  • This study analyzed total concentrations and existing forms of heavy metals in soils of Ulsan using a sequential extraction method. Soil samples were collected from 6 categorized areas including green, residential, heavy traffic, petrochemical industrial complex(IC), mechanical and shipbuilding IC, and non-ferrous metal IC areas. which represent different emission characteristics. The highest total concentrations of heavy metals by a sequential extraction analysis were observed in the soils collected from the non-ferrous metal IC area, followed by the mechanical and shipbuilding IC and heavy traffic areas. Dominant(> 50%) existing forms of Cd, Cr and Ni were residual forms followed by Fe and Mn oxides in almost areas. Residual fractions in the non-ferrous metal IC areas were relatively lower than those in other areas. However, the fractions of organic and sulphides in the IC areas were higher. The dominant farms of Cu were much different with the investigated areas. In most areas, the dominant forms of Pb and Zn were Fe and Mn oxides, followed by residual fraction for Pb. The exchangeable and carbonate fractions represent mobility of metallic elements in soils. They are also significantly affected by the environmental renditions, such as pHs of soil and rainfall. In this study the exchangeable and carbonate fractions were lower than other fractions. Because the total concentrations of heavy metals in the soils of the non-ferrous metal IC area were extremely high, however, the mobile fractions of heavy metals in the IC area would be significant. Thus a large amount of heavy metals can be released into plants, water bodies, and soils. Therefore, urgent measures, such as source control for soil remediation of heavy metals, in the non-ferrous metal IC areas are essentially required. Analysis results obtained from the sequential extraction and the aqua regia extraction showed a high correlation, whose determination coefficients(R2) of heavy metals except Cd approximately ranged from 0.7 to 0.9.

Carbon Monoxide Dispersion in an Urban Area Simulated by a CFD Model Coupled to the WRF-Chem Model (WRF-Chem 모델과 결합된 CFD 모델을 활용한 도시 지역의 일산화탄소 확산 연구)

  • Kwon, A-Rum;Park, Soo-Jin;Kang, Geon;Kim, Jae-Jin
    • Korean Journal of Remote Sensing
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    • v.36 no.5_1
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    • pp.679-692
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    • 2020
  • We coupled a CFD model to the WRF-Chem model (WRF-CFD model) and investigated the characteristics of flows and carbon monoxide (CO) distributions in a building-congested district. We validated the simulated results against the measured wind speeds, wind directions, and CO concentrations. The WRF-Chem model simulated the winds from southwesterly to southeasterly, overestimating the measured wind speeds. The statistical validation showed that the WRF-CFD model simulated the measured wind speeds more realistically than the WRF-Chem model. The WRF-Chem model significantly underestimated the measured CO concentrations, and the WRF-CFD model improved the CO concentration prediction. Based on the statistical validation results, the WRF-CFD model improved the performance in predicting the CO concentrations by taking complicatedly distributed buildings and mobiles sources of CO into account. At 04 KST on May 22, there was a downdraft around the AQMS, and airflow with a relatively low CO concentration was advected from the upper layer. Resultantly, the CO concentration was lower at the AQMS than the surrounding area. At 15 KST on May 22, there was an updraft around the AQMS. This resulted in a slightly higher CO concentration than the surroundings. The WRF-CFD model transported CO emitted from the mobile sources to the AQMS measurement altitude, well reproducing the measured CO concentration. At 18 KST on May 22, the WRF-CFD model simulated high CO concentrations because of high CO emission, broad updraft area, and an increase in turbulent diffusion cause by wind-shear increase near the ground.