Based on the simplification of cutting process,a series of numerical simulations were conducted using a 2-D discrete element method to explore the effects of embedded cracks with different dip angles on the rock fragm...Based on the simplification of cutting process,a series of numerical simulations were conducted using a 2-D discrete element method to explore the effects of embedded cracks with different dip angles on the rock fragmentation process,cutting characteristics and breaking efficiency.The results show that the simulated results are in a good agreement with previous theoretical study.The main crack propagates to the top tip of embedded crack,except when the dip angle is 90°.Side cracks which are more fully developed in the rocks containing embedded cracks tend to propagate towards the free surface.According to the history of vertical cutting force,it is shown that the peak force is decreased by embedded cracks.The study on cutting efficiency was conducted by combining the quantity of crack and cutting energy.And the results show that breaking efficiency can be treated as a decreasing or a increasing function when the dip angle is less or larger than 30°,respectively.Breaking efficiency is higher than that in intact rock when the dip angle is larger than 45°.展开更多
Transmitter identification(TxID) technique is used to diagnose the operation status of radio transmitters in DTV distributed transmission network.A new TxID method for digital video broadcasting-handheld (DVB-H) syste...Transmitter identification(TxID) technique is used to diagnose the operation status of radio transmitters in DTV distributed transmission network.A new TxID method for digital video broadcasting-handheld (DVB-H) system is proposed.Watermark is embedded in the DVB-H signal to form the composite signal.According to watermarking theory we demonstrate the required signal level for watermarking signal to achieve given bit error probability under different circumstance.By selecting the reference pattern to generate watermarking signal,peak-to-average power ratio(PAPR) of the transmitted signal can be improved.Simulation results show that even in wireless situation the receiver can distinguish the watermarking signal with low embedding strength, and distortion to the host signal can also be ignored.展开更多
基金Project(2013CB035401)supported by the National Basic Research Program of ChinaProject(51174228)supported by the National Natural Science Foundation of ChinaProject(71380100003)supported by Hunan Provincial Innovation Foundation for Postgraduate,China
文摘Based on the simplification of cutting process,a series of numerical simulations were conducted using a 2-D discrete element method to explore the effects of embedded cracks with different dip angles on the rock fragmentation process,cutting characteristics and breaking efficiency.The results show that the simulated results are in a good agreement with previous theoretical study.The main crack propagates to the top tip of embedded crack,except when the dip angle is 90°.Side cracks which are more fully developed in the rocks containing embedded cracks tend to propagate towards the free surface.According to the history of vertical cutting force,it is shown that the peak force is decreased by embedded cracks.The study on cutting efficiency was conducted by combining the quantity of crack and cutting energy.And the results show that breaking efficiency can be treated as a decreasing or a increasing function when the dip angle is less or larger than 30°,respectively.Breaking efficiency is higher than that in intact rock when the dip angle is larger than 45°.
文摘Transmitter identification(TxID) technique is used to diagnose the operation status of radio transmitters in DTV distributed transmission network.A new TxID method for digital video broadcasting-handheld (DVB-H) system is proposed.Watermark is embedded in the DVB-H signal to form the composite signal.According to watermarking theory we demonstrate the required signal level for watermarking signal to achieve given bit error probability under different circumstance.By selecting the reference pattern to generate watermarking signal,peak-to-average power ratio(PAPR) of the transmitted signal can be improved.Simulation results show that even in wireless situation the receiver can distinguish the watermarking signal with low embedding strength, and distortion to the host signal can also be ignored.