A low-overhead and reliable switch architecture for Network-on-Chips

This paper proposes and evaluates Low-overhead, Reliable Switch (LRS) architecture to enhance the reliability of Network-on-Chips (NoCs). The proposed switch architecture exploits information and hardware redundancies to eliminate retransmission of faulty flits. The LRS architecture creates a redundant copy of each newly received flit and stores the redundant flit in a duplicated flit buffer that is associated with the incoming channel of the flit. Flit buffers in the LRS are equipped with information redundancy to detect probable bit flip errors. When an error is detected in a flit buffer, its duplicated buffer is used to recover the correct value of the flit. In this way, the propagation of the erroneous flits in NoC is prevented without any need to credit signals and, retransmission buffers. Using an HDL-based NoC simulator, the LRS is compared to two other widely used reliability enhancement methods: the Switch-to-Switch (S2S) and the End-to-End (E2E) methods. The simulation results show that the LRS consumes less power and provides higher performance compared to those of the E2E and S2S methods. More importantly, unlike the E2E and the S2S methods, the LRS has constant overheads, which makes it applicable in all working conditions. To validate the comparison, an analytical performance and reliability model is developed for the LRS, S2S and E2E methods. The results of the model match those obtained from the simulations while the proposed model is significantly faster.     

Transient steel quality under non-isothermal conditions in a multi-strand billet caster tundish: part II. Effect of a flow-control device

A mathematical model was built to simultaneously analyse the effects of non-isothermal conditions and flow-control device on steel quality in a real steelmaking tundish. Liquid steel was used as the operating liquid with a step-input of 23° in a full-scale delta-shaped multi-strand billet caster tundish fitted with a standard impact pad (SIP). The changes in flow pattern and temperature fields of liquid steel in the tundish under isothermal, step-up and step-down conditions were thoroughly studied. Similar to the case of a bare tundish, buoyancy effects were seen to dominate at regions away from the ladle shroud. The presence of SIP modified the flow patterns and resulted into markedly different values of RRI as compared to bare tundish. Finally, the calculated results were qualitatively compared to results obtained from a real steelmaking tundish.     

水泥厂风机节能方法比较与选择

水泥厂风机的耗能较大,因此可开挖的节能空间和节能潜力也大。作者介绍了水泥厂风机节能运行的各种常用方法,分析了这些方法的优缺点;通过比较说明,变频器调速是水泥厂风机节能运行的最佳方法。