The TBS （telecommunications base stations） on remote sites in the northern part of Cameroon are mainly supplied by a system of two generating units. Only a few TBS located in the Waza and Benue National Parks are po...The TBS （telecommunications base stations） on remote sites in the northern part of Cameroon are mainly supplied by a system of two generating units. Only a few TBS located in the Waza and Benue National Parks are powered by a PV （photovoltaic） solar system to avoid any disturbance to wildlife. It is against this background that we decided to do a comparative study on these two systems. This study focuses on the reliability of electrical quantities, the environmental impact and the installation and operating costs of these two major systems namely the GU （generating unit） system comprising two generating units and the PV system. In conducting this study, we took a sample of TBS including those located in the Badjouma and Waza localities. After collecting data from mobile telephony operators, measurements of electrical quantities on the sites for twelve consecutive months and updating costs, their operation reveal indicators that are surprising, to say the least. Concerning the reliability index, the PV system is estimated at 99.9% as against 97.8% for the GU system. As for environmental impact, the mass of CO2 released by the GU system reached 1,707.5 tons in 25 years for a single TBS while the PV system produced no emissions. In addition to its contribution to climate change, the GU system pollutes its immediate environment through the spillage of waste and production of deafening noise. On the other hand, economic analysis shows mixed results. The GU system has a lower installation cost of $6,640 as against $174,550 for the PV system, whose investment cost is its main handicap. Regarding operating costs, the GU system peaks at $923,940 in 25 years while the PV system requires only $487,550 for the same duration.展开更多
This paper describes a design method and construction of a PV hybrid system for household electrification in remote area which has typical important electrical loads for daily life such as television, refrigerator, el...This paper describes a design method and construction of a PV hybrid system for household electrification in remote area which has typical important electrical loads for daily life such as television, refrigerator, electric fan, coffee maker, and radio. The paper presents the design method which is a short and correct method for the PV Hybrid system design. The result of the proposed design method is finally simulated by Homer software to optimize and prove the result. From the simulation, the output shows that the proposed method is proper for using to design the sizing of PV hybrid system. After the design, a PV hybrid system is constructed accordingly to the system design. A PV hybrid prototype is constructed as a small house which is specially constructed for demonstration of the proposed system. The PV hybrid system therefore has the size of PV 1.8 kWp, battery 20 kWh, and diesel generator 3 kW. After a long implementation of the system, the results of monitored data show that the designed PV hybrid system can deliver the power to the house continually 24 hours as it is originally designed. This can ensure that the proposed method of PV hybrid system design is correct and can be used for design the PV hybrid system for electrical utility in the remote area where has no an electric grid.展开更多
To address the challenges of non-cooperative and remote acoustic detection, an all-fiber laser Doppler vibrometer(LDV) is established. The all-fiber LDV system can offer the advantages of smaller size, lightweight des...To address the challenges of non-cooperative and remote acoustic detection, an all-fiber laser Doppler vibrometer(LDV) is established. The all-fiber LDV system can offer the advantages of smaller size, lightweight design and robust structure, hence it is a better fit for remote speech detection. In order to improve the performance and the efficiency of LDV for long-range hearing, the speech enhancement technology based on optimally modified log-spectral amplitude(OM-LSA) algorithm is used. The experimental results show that the comprehensible speech signals within the range of 150 m can be obtained by the proposed LDV. The signal-to-noise ratio(SNR) and mean opinion score(MOS) of the LDV speech signal can be increased by 100% and 27%, respectively, by using the speech enhancement technology. This all-fiber LDV, which combines the speech enhancement technology, can meet the practical demand in engineering.展开更多
The adaptive optics system on the 2.16 m telescope is modeled and simulated using an ends-to-ends Monte Carlo method in this paper.Under the optimized parameters,the Strehl ratio can be increased from about 0.02 to mo...The adaptive optics system on the 2.16 m telescope is modeled and simulated using an ends-to-ends Monte Carlo method in this paper.Under the optimized parameters,the Strehl ratio can be increased from about 0.02 to more than 0.2 in the J,H and K bands with a classical adaptive optics system.Based on the simulation results,the practical system design is also considered and discussed.展开更多
文摘The TBS （telecommunications base stations） on remote sites in the northern part of Cameroon are mainly supplied by a system of two generating units. Only a few TBS located in the Waza and Benue National Parks are powered by a PV （photovoltaic） solar system to avoid any disturbance to wildlife. It is against this background that we decided to do a comparative study on these two systems. This study focuses on the reliability of electrical quantities, the environmental impact and the installation and operating costs of these two major systems namely the GU （generating unit） system comprising two generating units and the PV system. In conducting this study, we took a sample of TBS including those located in the Badjouma and Waza localities. After collecting data from mobile telephony operators, measurements of electrical quantities on the sites for twelve consecutive months and updating costs, their operation reveal indicators that are surprising, to say the least. Concerning the reliability index, the PV system is estimated at 99.9% as against 97.8% for the GU system. As for environmental impact, the mass of CO2 released by the GU system reached 1,707.5 tons in 25 years for a single TBS while the PV system produced no emissions. In addition to its contribution to climate change, the GU system pollutes its immediate environment through the spillage of waste and production of deafening noise. On the other hand, economic analysis shows mixed results. The GU system has a lower installation cost of $6,640 as against $174,550 for the PV system, whose investment cost is its main handicap. Regarding operating costs, the GU system peaks at $923,940 in 25 years while the PV system requires only $487,550 for the same duration.
文摘This paper describes a design method and construction of a PV hybrid system for household electrification in remote area which has typical important electrical loads for daily life such as television, refrigerator, electric fan, coffee maker, and radio. The paper presents the design method which is a short and correct method for the PV Hybrid system design. The result of the proposed design method is finally simulated by Homer software to optimize and prove the result. From the simulation, the output shows that the proposed method is proper for using to design the sizing of PV hybrid system. After the design, a PV hybrid system is constructed accordingly to the system design. A PV hybrid prototype is constructed as a small house which is specially constructed for demonstration of the proposed system. The PV hybrid system therefore has the size of PV 1.8 kWp, battery 20 kWh, and diesel generator 3 kW. After a long implementation of the system, the results of monitored data show that the designed PV hybrid system can deliver the power to the house continually 24 hours as it is originally designed. This can ensure that the proposed method of PV hybrid system design is correct and can be used for design the PV hybrid system for electrical utility in the remote area where has no an electric grid.
基金supported by the National Natural Science Foundation of China(No.61205143)
文摘To address the challenges of non-cooperative and remote acoustic detection, an all-fiber laser Doppler vibrometer(LDV) is established. The all-fiber LDV system can offer the advantages of smaller size, lightweight design and robust structure, hence it is a better fit for remote speech detection. In order to improve the performance and the efficiency of LDV for long-range hearing, the speech enhancement technology based on optimally modified log-spectral amplitude(OM-LSA) algorithm is used. The experimental results show that the comprehensible speech signals within the range of 150 m can be obtained by the proposed LDV. The signal-to-noise ratio(SNR) and mean opinion score(MOS) of the LDV speech signal can be increased by 100% and 27%, respectively, by using the speech enhancement technology. This all-fiber LDV, which combines the speech enhancement technology, can meet the practical demand in engineering.
文摘The adaptive optics system on the 2.16 m telescope is modeled and simulated using an ends-to-ends Monte Carlo method in this paper.Under the optimized parameters,the Strehl ratio can be increased from about 0.02 to more than 0.2 in the J,H and K bands with a classical adaptive optics system.Based on the simulation results,the practical system design is also considered and discussed.
