Environmental laws are increasing and changing faster than they can be implemented in the construction industry. This is especially important for federal facilities and environmental construction because federal agenc...
The present study deals with the limit analysis of masonry walls with rectangular openings by an equivalent shear panel model. Many experimental results on masonry walls with rectangular openings subject to both verti...
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ISBN:
(纸本)1853129682
The present study deals with the limit analysis of masonry walls with rectangular openings by an equivalent shear panel model. Many experimental results on masonry walls with rectangular openings subject to both vertical and horizontal loads show importance of shear resistance of wall panels. Based upon these experimental results, in-plane failure patterns of single masonry walls are categorized into a) the shear diagonal crack opening, b) local panel rocking, c) bed joint sliding, and d) full or partial overturning of an entire wall. The equivalent shear panel model can evaluate strength for typical in-plane failure patterns due to earthquake damages. By means of the present model the limit analysis of masonry walls can be formulated as a searching problem for a collapse mode with minimum failure load, to which the genetic algorithm (GA) can be applied. The application of both the present shear panel model and the GA is illustrated in a numerical example of a masonry wall with rectangular openings subjected to constant vertical and incremental horizontal loads.
Numerical simulation code is developed to study the formation of liquid drops from a nozzle into another quiescent liquid. The Navier-Stokes equations for two immiscible, incompressible, Newtonian fluids are solved on...
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ISBN:
(纸本)0791836967
Numerical simulation code is developed to study the formation of liquid drops from a nozzle into another quiescent liquid. The Navier-Stokes equations for two immiscible, incompressible, Newtonian fluids are solved on a fixed, staggered grid of cylindrical axisymmetric coordinates. Interfacial motion is captured using a Front-Tracking Method. The time variation of interfacial shape simulated by the code is in excellent agreement with experiments. Simulation results show that the viscosity ratio affects the size of the satellite drops.
A novel frequency domain Doppler diversity technique for OFDM systems is proposed. The received OFDM signal is first frequency shifted to generate various diversity branches. After demodulation, branch outputs are ind...
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A novel frequency domain Doppler diversity technique for OFDM systems is proposed. The received OFDM signal is first frequency shifted to generate various diversity branches. After demodulation, branch outputs are individually weighted and added together. For Doppler spread signal, it alters fading statistics and improves the bit error rate. Extensive simulations show that combining three diversity branches with proper frequency shifts reduces BER by an order when the normalized Doppler spread is larger than 0.3.
The space-time-frequency processing for OFDM wireless mobile communications was presented. The novel space-time-frequency processing schemes for OFDM mobile communication systems were implemented by using antenna arra...
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The space-time-frequency processing for OFDM wireless mobile communications was presented. The novel space-time-frequency processing schemes for OFDM mobile communication systems were implemented by using antenna arrays. It was stated that, when the angular spread is small, multiple antennas might not be able to provide space diversity.
A study was performed on Doppler diversity for orthogonal frequency-division multiplexing (OFDM) wireless mobile communications. A novel time-frequency processing scheme was developed to exploit Doppler diversity. The...
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A study was performed on Doppler diversity for orthogonal frequency-division multiplexing (OFDM) wireless mobile communications. A novel time-frequency processing scheme was developed to exploit Doppler diversity. The extensive simulations showed that the proposed time-frequency MMSE processing scheme altered the statistics of the fading to improve BER significantly.
Structural control technology offers many new ways to protect structures from natural hazards. A comprehensive experimental investigation was carried out in The Hong Kong polytechnic University to apply multiple magne...
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Structural control technology offers many new ways to protect structures from natural hazards. A comprehensive experimental investigation was carried out in The Hong Kong polytechnic University to apply multiple magnetorheological (MR) dampers to connect podium structures to tall buildings for preventing seismic damage due to sudden change of lateral stiffness and mass. A slender 12-storey building model and a relatively stiff 3-storey building model were constructed to represent a tall building and a podium structure respectively. MR dampers were used to link the 3-storey building to the 12-storey building at each of the bottom three storeys. The two buildings without any connection and with a rigid connection were first tested under scaled El Centro 1940 N-S ground motion. A test was then performed on the two buildings connected by MR dampers manipulated by a semi-active logic control algorithm. Finally, reliability of the semi-active control system and robustness of the semi-active logic control algorithm were experimentally investigated. The experimental results have demonstrated that the multiple MR dampers with the semi-active logic control algorithm can achieve a significant reduction in seismic responses of both buildings with very small power requirement. The proposed semi-active control system is of highly reliable and robust.
A novel frequency domain Doppler diversity technique for OFDM systems is proposed. The received OFDM signal is first frequency shifted to generate various diversity branches. After demodulation, branch outputs are ind...
详细信息
ISBN:
(纸本)0780377575
A novel frequency domain Doppler diversity technique for OFDM systems is proposed. The received OFDM signal is first frequency shifted to generate various diversity branches. After demodulation, branch outputs are individually weighted and added together. For Doppler spread signal, it alters fading statistics and improves the bit error rate. Extensive simulations show that combining three diversity branches with proper frequency shifts reduces BER by an order when the normalized Doppler spread is larger than 0.3.
Novel space-time-frequency processing schemes for OFDM mobile communication systems are implemented using antenna arrays, tap delay lines and Doppler branches to exploit angular spread, delay spread and Doppler spread...
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ISBN:
(纸本)0780377575
Novel space-time-frequency processing schemes for OFDM mobile communication systems are implemented using antenna arrays, tap delay lines and Doppler branches to exploit angular spread, delay spread and Doppler spread, respectively.
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