The hierarchical hub covering facility location problems are applied to distribution systems, transportation, waste disposal, treatment services, emergency services and remote communication. The problems attempt to determine the location of service providers' facilities at different levels and specify their linking directions in order to reduce costs and to establish an appropriate condition in...

In this paper we study two echelon multi-server tandom queueing systems where customers arrive according to a poisson process with two different rates. The service rates at both echelons are independent of each other. The service times of customers is assumed to be completed in two stages. The service times at each stage are exponentially distributed. At the first stage, the customers may balk ...

This paper proposes an advanced distribution automation planning problem in which emergency-based demand response plans are incorporated during service restoration process. The fitness function of this planning problem consists of various costs associated with fault occurrence in electric distribution systems consisting of the total yearly cost of customers’ interruptions, the total annualized ...

Quality of Service (QoS) refers to a set of rules or techniques that help the network administrators use the available network resources optimally to manage the effects of congestion and to treat the applications according to their needs. The differentiated services architecture (DiffServ) allows providing quality of service to users. The major DiffServ premise is that individual flows with sim...

in this paper, the staff assignment problem considering cross-training of caregivers in health care systems is addressed to determine which staff should be cross-trained for each service and how they should be assigned to services. a bi-objective non-linear mathematical programming model is presented where the first objective function aims to minimize workload balancing, cross-training as well ...

This paper presents a metamodel that addresses service system design and innovation by traversing and integrating three essential layers, service activities, service systems, and value constellations. The metamodel's approach to service systems as service-in-operation is an alternative to another currently used approach that views service systems as systems of economic exchange. The metamodel a...

This paper presents a metamodel that addresses service system design and innovation by traversing and integrating three essential layers, service activities, service systems, and value constellations. The metamodel's approach to service systems as service-inoperation is an alternative to another currently used approach that views service systems as systems of economic exchange. The metamodel ad...

quality of service (qos) is an important issue in the design and management of web service composition. qos in web services consists of various non-functional factors, such as execution cost, execution time, availability, successful execution rate, and security. in recent years, the number of available web services has proliferated, and then offered the same services increasingly. the same web ...