in this paper we present the problem of designing a three level hub center network. in our network, the top level consists of a complete network where a direct link is between all central hubs.  the second and third levels consist of star networks that connect the hubs to central hubs and the demand nodes to hubs and thus to central hubs, respectively. we model this problem in an incomplete net...

in this paper smart operation of micro energy hub is presented. energy hub system consists of certain energy hubs and interconnectors that are coordinated by energy hub system operator. an energy hub contains several converters and storages to serve demanded services in most efficient manner from available energy carriers. in this paper, the flexibility of energy delivery point is enhanced u...

the existing works considering the flow-based discount factor in the hub and spoke problems, assume that increasing the amount of flow passing through each edge of network continuously decreases the unit flow transportation cost. although a higher volume of flow allows for using wider links and consequently cheaper transportation, but the unit of flow enjoys more discounts, quite like replacing...

in this paper, a robust model presented is developed for hub covering flow problem in which hubs have capacity. this problem has two objective functions converting to a single-objective problem by using weighting method. firstly, the problem will be formulated in a certain case. then, by considering the demand as a non-random variable, it will be modeled by robust optimization. finally, by usin...

The goals of hub location problems are finding the location of hub facilities and determining the allocation of non-hub nodes to these located hubs. In this work, we discuss the multi-modal single allocation capacitated p-hub covering problem over fully interconnected hub networks. Therefore, we provide a formulation to this end. The purpose of our model is to find the location of hubs and the ...

In this paper smart operation of micro energy hub is presented. Energy hub system consists of certain energy hubs and interconnectors that are coordinated by energy hub system operator. An energy hub contains several converters and storages to serve demanded services in most efficient manner from available energy carriers. In this paper, the flexibility of energy delivery point is enhanced u...

the biggest challenges faced in big cities are greenhouse gas emission and growing energy needs. efficient utilization of existing infrastructures has a prominent role in response to the challenges. energy hub approach embraces performance of different energy networks. energy hub is defined as a super node in electrical system receiving distinctive energy carriers such as gas and electricity in...

background: current who best infection control practices for injections do not address the use of hub cutters due to insufficient evidence on safety and efficacy. objective: to assess the impact of the use of hub cutters on 1) the frequency of needle-stick injuries (nsis) and other blood exposures among workers and 2) the volume of sharps waste in a mass vaccination campaign setting. methods: d...