Conventional IP routers are passive devices that accept packets and perform the routing function on any input. Usually the tail-drop (TD) strategy is used where the input which exceeds the buffer capacity are simply dropped. In active queue management (AQM) methods routers manage their buffers by dropping packets selectively. We study one of the AQM methods called as random exponential marking ...

Capacity drop is the critical phenomenon that triggers traffic congestion, while evolution very complex during a capacity drop. This study applied empirical vehicle trajectory data to explore characteristics at tunnel bottleneck section. We first construct analysis model using image processing technology extract high-precision trajectories. then analyze of process area. The results show dynamic...

Circular drop manholes are widely implemented for steep catchments in urban drainage networks. Poor downstream hydraulic transition processes of a manhole system, i.e., the formation jump near outlet entrance, and sudden from free surface to pressurized flow with bursts air outflow pipe can severely constraint capacity water conveyance. In this paper, we defined four basic stages that indicate ...

computational fluid dynamics (cfd) simulations of gas-solid flow through a positive low-pressure pneumatic conveyor were performed using eulerian-eulerian framework. pressure drop in pneumatic conveying pipelines, creation and destruction of plugs along the horizontal and vertical pipes, effect of 90° elbows and u-bends on cross-section concentrations, and rope formation and dispersion were num...

High-capacity multiwavelength ring networks with bidirectional WDM add/drop multiplexer (WADM) is analyzed and demonstrated. All channels can be added/ dropped independently in each direction. The capacity of a bidirectional ring is found to be approximately twice that of an unidirectional ring. An eight-wavelength WADM is demonstrated for a data rate of 10 Gb/s per channel, providing an overal...

here, we propose an add-drop and a channel drop filter based on two-dimensional photonic crystal all circular ring resonators. these structures are made of a square lattice of silicon rods with the refractive index n1=3.464 surrounded by air (with refractive index n2=1). the broadest photonic band gap occurs at the filling ratio of r/a = 0.17. two linear defect w1 waveguides couple to the ring....

release  volatile  organic  compounds  (vocs)  as  environmental  and  occupational  pollutant  cause  macro perspective affect such as climate change, humans and economic consequences. although fixed bed absorber is widely used as a controlling method because of its economically and availability, but these absorbers are facing some issue like high pressure drop, non-uniform distribution of flu...

The convective heat transfer and pressure drop of water based Al2O3 nanofluid in a horizontal tube subject to constant wall temperature condition is investigated by computational fluid dynamic (CFD) method. The Al2O3 nanofluid at five volume concentration of 0.1, 0.5, 1.0, 1.5 and 2 % are applied as a non Newtonian power law and Newtonian fluid with experimentally measured properties of density...