In 5G systems, massive multiple-input multiple-output (MIMO) has been adopted in base stations (BSs) to improve spectral efficiency and coverage. The traditional conductive performance test techniques are challenging ...In 5G systems, massive multiple-input multiple-output (MIMO) has been adopted in base stations (BSs) to improve spectral efficiency and coverage. The traditional conductive performance test techniques are challenging due to the unaffordable cost and high complexity when testing a large number of antennas. To solve this problem, the over-the-air (OTA) test has been presented, in which probe selection is the key to reduce the number of channel emulators and probes. In this paper, a novel artificial bee colony (ABC) algorithm is introduced to enhance the efficiency and accuracy of probe selection procedure. A sectoring- based multi-probe anechoic chamber (MPAC) is built to evaluate the throughput performance of massive MIMO equipped in 5G BS. In addition, link level simulation is carried out to evaluate the proposal’s performance gain under the commercial network assumptions, where the average throughput of three velocity is given with different SNR region. The results suggest that OTA chamber and multi-probe wall are available not only for 5G BSs, but also for user equipments (UEs) with end-to-end communication.展开更多
Carbon dioxides (CO<sub>2</sub>) concentration has become much higher every year and this has already become the global issue. Lichen is a symbiotic organism that is best known as the air pollution indicat...Carbon dioxides (CO<sub>2</sub>) concentration has become much higher every year and this has already become the global issue. Lichen is a symbiotic organism that is best known as the air pollution indicator. Based on its frequency and diversity distribution, the level of pollution that has been made can be determined. This re-search was conducted in UKM Fernarium Free Air Carbon Dioxides Enrichment Station (FACE Station) with lichen frequencies and diversities observed and analyzed statistically and graphically. Seven species of li-chens were found at the sampling locations. Findings showed that there was significant relationship in lichen frequency and diversity distribution under elevated CO<sub>2</sub> inside FACE Station with its surrounding.展开更多
The work of “Monitoring and Evaluation of Air Pollution” the main aim of this work is to measure the concentrations of gases which include CO<sub>2</sub>, CO, NO<sub>x</sub>, SO<sub>x&l...The work of “Monitoring and Evaluation of Air Pollution” the main aim of this work is to measure the concentrations of gases which include CO<sub>2</sub>, CO, NO<sub>x</sub>, SO<sub>x</sub> and thermal radiation and carry out an analysis of the measured data. This experiment was scheduled to take place at Egbema flow station which is managed by NPDC (Nigerian Petroleum Development Commission) Shell location 2 in Obiakpu, Ohaji Imo state. The bad effects of these pollutant gases on the community can include cause of diseases to plants and animals, causes of physical ailments in the respiratory tract of humans, and death and degradation of the surrounding environment. The parameters measured during this exercise include the distance from the flow station, latitude and longitude of the distance measured on the earth’s surface, time for the experiment and the concentration of pollutant gases. The instrument used includes CO meter, CO<sub>2</sub> meter, SO<sub>x</sub> and NO<sub>x</sub> meters, and thermal radiation meter. The gases were measured in three different time intervals between 10:50 am - 11:23 am (for CO: 0.02 ppm, 0.01 ppm, 0 ppm, 0 ppm, 0.01 ppm, 0 ppm;for CO<sub>2</sub>: 0.04 ppm, 0.01 ppm, 0.01 ppm, 0.02 ppm, 0.01 ppm, 0 ppm;for SO<sub>x</sub>: 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>;for NO<sub>x</sub>: 0.127 mg/m<sup>3</sup>, 0.098 mg/m<sup>3</sup>, 0.12 mg/m<sup>3</sup>, 0.122 mg/m<sup>3</sup>, 0.113 mg/m<sup>3</sup>, 0.103 mg/m<sup>3</sup>;for thermal radiation: 57.4 W/m<sup>2</sup>, 61.5 W/m<sup>2</sup>, 65.1 W/m<sup>2</sup>, 64.9 W/m<sup>2</sup>, 81.9 W/m<sup>2</sup>, 148.3 W/m<sup>2</sup>), 1:30 pm - 2:13 pm (for CO: 0.01 ppm, 0.02 ppm, 0 ppm, 0 ppm, 0.1 ppm, 0 ppm;for CO<sub>2</sub>: 0.01 ppm, 0.01 ppm, 0.01 ppm, 0.01 ppm, 0 ppm, 0 ppm;for SO<sub>x</sub>: 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>;for NO<sub>x</sub>: 0.122 mg/m<sup>3</sup>, 0.117 mg/m<sup>3</sup>, 0.114 mg/m<sup>3</sup>, 0.115 mg/m<sup>3</sup>, 0.122 mg/m<sup>3</sup>, 0.11 mg/m<sup>3</sup>;for thermal radiation: 120.5 W/m<sup>2</sup>, 132.8 W/m<sup>2</sup>, 156.7 W/m<sup>2</sup>, 170.5 W/m<sup>2</sup>, 148.5 W/m<sup>2</sup>, 95.1 W/m<sup>2</sup>) and 5 pm - 5:37 pm (for CO: 0.02 ppm, 0.1 ppm, 0.1 ppm, 0 ppm, 0 ppm, 0 ppm;for CO<sub>2</sub>: 0.03 ppm, 0.2 ppm, 0.1 ppm, 0.1 ppm, 0 ppm, 0.1 ppm;for SO<sub>x</sub>: 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>;for NO<sub>x</sub>: 0.128 mg/m<sup>3</sup>, 0.118 mg/m<sup>3</sup>, 0.119 mg/m<sup>3</sup>, 0.117 mg/m<sup>3</sup>, 0.124 mg/m<sup>3</sup>, 0.114 mg/m<sup>3</sup>;for thermal radiation: 121.4 W/m<sup>2</sup>, 133.3 W/m<sup>2</sup>, 160.2 W/m<sup>2</sup>, 177 W/m<sup>2</sup>, 161.4 W/m<sup>2</sup>, 97.2 W/m<sup>2</sup>) at distances of 0 m, 100 m, 300 m, 500 m, 1000 m and 1500 m respectively. From the values gotten from the gas concentration measurements, we can say that SO<sub>x</sub> gases are either minute or not available in the environment. Also, from the graph analysis carried out on the gases, we can also say that CO<sub>2</sub> concentration is either increasing or at the same level throughout the distance while the concentrations of NO<sub>x</sub>, CO and thermal radiation reduce with increasing distance. On the part of the “averaging time model” used in the analysis, we can say that at increasing averaging times the concentration of gases reduces. Analysis of whether the environment is polluted and with which gas exactly is also carried out using the Air quality index and it was deduced that the environment is polluted with NO<sub>x</sub> gases because the concentration is above the normal environmental ambient temperature.展开更多
基金supported by the State Major Science and Technology Special Projects under Grant No. 2018ZX03001028-003
文摘In 5G systems, massive multiple-input multiple-output (MIMO) has been adopted in base stations (BSs) to improve spectral efficiency and coverage. The traditional conductive performance test techniques are challenging due to the unaffordable cost and high complexity when testing a large number of antennas. To solve this problem, the over-the-air (OTA) test has been presented, in which probe selection is the key to reduce the number of channel emulators and probes. In this paper, a novel artificial bee colony (ABC) algorithm is introduced to enhance the efficiency and accuracy of probe selection procedure. A sectoring- based multi-probe anechoic chamber (MPAC) is built to evaluate the throughput performance of massive MIMO equipped in 5G BS. In addition, link level simulation is carried out to evaluate the proposal’s performance gain under the commercial network assumptions, where the average throughput of three velocity is given with different SNR region. The results suggest that OTA chamber and multi-probe wall are available not only for 5G BSs, but also for user equipments (UEs) with end-to-end communication.
文摘Carbon dioxides (CO<sub>2</sub>) concentration has become much higher every year and this has already become the global issue. Lichen is a symbiotic organism that is best known as the air pollution indicator. Based on its frequency and diversity distribution, the level of pollution that has been made can be determined. This re-search was conducted in UKM Fernarium Free Air Carbon Dioxides Enrichment Station (FACE Station) with lichen frequencies and diversities observed and analyzed statistically and graphically. Seven species of li-chens were found at the sampling locations. Findings showed that there was significant relationship in lichen frequency and diversity distribution under elevated CO<sub>2</sub> inside FACE Station with its surrounding.
文摘The work of “Monitoring and Evaluation of Air Pollution” the main aim of this work is to measure the concentrations of gases which include CO<sub>2</sub>, CO, NO<sub>x</sub>, SO<sub>x</sub> and thermal radiation and carry out an analysis of the measured data. This experiment was scheduled to take place at Egbema flow station which is managed by NPDC (Nigerian Petroleum Development Commission) Shell location 2 in Obiakpu, Ohaji Imo state. The bad effects of these pollutant gases on the community can include cause of diseases to plants and animals, causes of physical ailments in the respiratory tract of humans, and death and degradation of the surrounding environment. The parameters measured during this exercise include the distance from the flow station, latitude and longitude of the distance measured on the earth’s surface, time for the experiment and the concentration of pollutant gases. The instrument used includes CO meter, CO<sub>2</sub> meter, SO<sub>x</sub> and NO<sub>x</sub> meters, and thermal radiation meter. The gases were measured in three different time intervals between 10:50 am - 11:23 am (for CO: 0.02 ppm, 0.01 ppm, 0 ppm, 0 ppm, 0.01 ppm, 0 ppm;for CO<sub>2</sub>: 0.04 ppm, 0.01 ppm, 0.01 ppm, 0.02 ppm, 0.01 ppm, 0 ppm;for SO<sub>x</sub>: 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>;for NO<sub>x</sub>: 0.127 mg/m<sup>3</sup>, 0.098 mg/m<sup>3</sup>, 0.12 mg/m<sup>3</sup>, 0.122 mg/m<sup>3</sup>, 0.113 mg/m<sup>3</sup>, 0.103 mg/m<sup>3</sup>;for thermal radiation: 57.4 W/m<sup>2</sup>, 61.5 W/m<sup>2</sup>, 65.1 W/m<sup>2</sup>, 64.9 W/m<sup>2</sup>, 81.9 W/m<sup>2</sup>, 148.3 W/m<sup>2</sup>), 1:30 pm - 2:13 pm (for CO: 0.01 ppm, 0.02 ppm, 0 ppm, 0 ppm, 0.1 ppm, 0 ppm;for CO<sub>2</sub>: 0.01 ppm, 0.01 ppm, 0.01 ppm, 0.01 ppm, 0 ppm, 0 ppm;for SO<sub>x</sub>: 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>;for NO<sub>x</sub>: 0.122 mg/m<sup>3</sup>, 0.117 mg/m<sup>3</sup>, 0.114 mg/m<sup>3</sup>, 0.115 mg/m<sup>3</sup>, 0.122 mg/m<sup>3</sup>, 0.11 mg/m<sup>3</sup>;for thermal radiation: 120.5 W/m<sup>2</sup>, 132.8 W/m<sup>2</sup>, 156.7 W/m<sup>2</sup>, 170.5 W/m<sup>2</sup>, 148.5 W/m<sup>2</sup>, 95.1 W/m<sup>2</sup>) and 5 pm - 5:37 pm (for CO: 0.02 ppm, 0.1 ppm, 0.1 ppm, 0 ppm, 0 ppm, 0 ppm;for CO<sub>2</sub>: 0.03 ppm, 0.2 ppm, 0.1 ppm, 0.1 ppm, 0 ppm, 0.1 ppm;for SO<sub>x</sub>: 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>, 0 mg/m<sup>3</sup>;for NO<sub>x</sub>: 0.128 mg/m<sup>3</sup>, 0.118 mg/m<sup>3</sup>, 0.119 mg/m<sup>3</sup>, 0.117 mg/m<sup>3</sup>, 0.124 mg/m<sup>3</sup>, 0.114 mg/m<sup>3</sup>;for thermal radiation: 121.4 W/m<sup>2</sup>, 133.3 W/m<sup>2</sup>, 160.2 W/m<sup>2</sup>, 177 W/m<sup>2</sup>, 161.4 W/m<sup>2</sup>, 97.2 W/m<sup>2</sup>) at distances of 0 m, 100 m, 300 m, 500 m, 1000 m and 1500 m respectively. From the values gotten from the gas concentration measurements, we can say that SO<sub>x</sub> gases are either minute or not available in the environment. Also, from the graph analysis carried out on the gases, we can also say that CO<sub>2</sub> concentration is either increasing or at the same level throughout the distance while the concentrations of NO<sub>x</sub>, CO and thermal radiation reduce with increasing distance. On the part of the “averaging time model” used in the analysis, we can say that at increasing averaging times the concentration of gases reduces. Analysis of whether the environment is polluted and with which gas exactly is also carried out using the Air quality index and it was deduced that the environment is polluted with NO<sub>x</sub> gases because the concentration is above the normal environmental ambient temperature.