We consider the problem of choosing the holding cost in inventory models. Traditionally, the cost of holding inventory is assumed to increase linearly with a rate that is equal to a percentage of the product value. This since the capital cost is believed to make up the main part of the cost. However, recent research indicates that this is not necessarily the case. In the present work, we presen...

Different uses of a road network call for the consideration of different travel costs: in route planning, travel time and distance are typically considered, and green house gas (GHG) emissions are increasingly being considered. Further, costs such as travel time and GHG emissions are time-dependent and uncertain. To support such uses, we propose techniques that enable the construction of a mult...

In this thesis we contribute to the understanding of the pivotal role of the temporal dimension in networked social systems, previously neglected and now uncovered by the data revolution recently blossomed in this field. To this aim, we first introduce the time-varying networks formalism and analyze some empirical data of social dynamics, extensively used in the rest of the thesis. We discuss t...

The spread of an infection on a real-world social network is determined by the interplay of two processes – the dynamics of the network, whose structure changes over time according to the encounters between individuals, and the dynamics on the network, whose nodes can infect each other after an encounter. Physical encounter is the most common vehicle for the spread of infectious diseases, but d...

Demand correlation among two interacting items is common in real-life markets. Sometimes demand of the first item would trigger additional demand toward the second item, but not vice versa. For items with decreasing demand in time, the longer is the selling period, the less the demand and the higher the inventory cost. This paper develops the related inventory model during which two deteriorati...

We analyze two scheduling problems for a queueing system with a single server and two customer classes. Each class has its own renewal arrival process, general service time distribution, and holding cost rate. In the first problem, a setup cost is incurred when the server switches from one class to the other, and the objective is to minimize the long-run expected average cost of holding custome...

this paper focuses on the non-fragile guaranteed cost control problem for a class of t-s fuzzy time-varying delay systems with local bilinear models. the objective is to design a non-fragile guaranteed cost state feedback controller via the parallel distributed compensation (pdc) approach such that the closed-loop system is delay-dependent asymptotically stable and the closed-loop performance i...

in this paper the numerical analysis of flow and time dependent heat transfer of micro-tube conveying nanofluid in laminar flow is investigated. in this study, convection heat transfer of nanofluid and base fluid and transient analysis for time-varying heat flux for time step of 0.0001 second are elucidated. it is observed that the pumping power of nanofluid flowing and the maximum temperature ...

Consensus problems in time-varying networks are studied in this paper. We consider two cases. In the first case, the networks are basically connected and the conditions for reaching consensus are described by means of the algebraic properties of connectivity for network graph. In the second case, the networks are possibly disconnected all time. A concept called integral connectivity of networks...