Urban landscape structure anatomy:Structure patterns and typology identification in the space-time of Setif City,Algeria

The definition of urban form and its elements raises a wide debate in urban morphology.This study presents a proposal to understand the structuring of the urban landscape of Setif City over 170 years(1848-2018)by abstracting its main elements into permanent structure(PSUL).It corresponds to the street network,more static to the change of the town plan,and flexible structure(FSul),more resilient to change and explains the superimpositions of morphological components(plot,building,and land use).This work aims to identify typological patterns of structures suggested in space-time through the inspection of the growth of the street network and the filling of morphological layers framed by the concept of urbanity.The methodology is based on syntactic(diachronic)morphogenetic analysis,with statistical analyses as unsupervised classification.Results indicate that PSUL presents an accumulation of microincrements produced with a similar degree of coherence in different urban fabrics,which explain the local patterns of street network structuring.The typology of FSul patterns indicates an unbalanced growth by the arrangement between morphological elements,resulting in a variation in the degree of urbanity.

Research on a six-phase permanent magnet synchronous motor system at dual-redundant and fault tolerant modes in aviation application

With the development of more/all electrical aircraft technology, an electro-mechanical actuator（EMA） is more and more used in an aircraft actuation system. The motor system, as the crucial part of an EMA, usually adopts the redundancy technology or fault tolerance technology to improve the reliability. To compare the performances of these two motor systems, a 10-pole/12-slot six-phase permanent magnet synchronous motor（PMSM） is designed with the concentrated single-layer winding, which is able to operate at dual-redundant and fault tolerant modes.Furthermore, the position servo performances of the six-phase PMSM at dual-redundant and fault tolerant modes are analyzed, including the normal and fault conditions. In addition, a variable structure proportional-integral-derivative（PID） control strategy is proposed to solve the performance degradation problem caused by phase current saturation. Simulation and experimental results show that the fault tolerant PMSM has a better position servo performance than the dual-redundant PMSM, and the variable structure PID control strategy is able to improve the performance due to phase current saturation.