there is little consensus on the corporate diversification-efficiency relationship in the diversification literature. according to the corporate diversification, firms have a tendency to get more market share with diversifying in the local segment or in the international market. theoretically, a contradictory exists between the profitable strategy and the value reducing strategy in the diversif...

parcel delivery is a complex logistic service, as it serves many small or medium-sized customers who may send or receive parcels. modeling such delivery system needs to integrate two different research areas of hub location and vehicle routing. as it totally depends on the network and the linkage of the nodes, in this paper, some door-to-door service providers are taken into account to provide ...

Wireless sensor networks are often located in areas where access to them is difficult or dangerous. Today, in wireless sensor networks, cluster-based routing protocols by dividing sensor nodes into distinct clusters and selecting local head-clusters to combine and send information of each cluster to the base station and balanced energy consumption by network nodes, get the best performance ...

this study tries to codify a proper mathematical model which can be predict the costs of repair and maintaining the tractors as precisely as possible for three common models of tractors in shahid beheshti cultivation firm in andimeshk-ahvaz road of dezfoul. studied tractors include: newhland tm155 tractor which is chosen from the most perfect file of 10 tractor machines and jandier tractor-3140...