Mathematical formulation of quantum circuit design problems in networks of quantum computers

In quantum circuit design, the question arises how to distribute qubits, used in algorithms, over the various quantum computers, and how to order them within a quantum computer. In order to evaluate these problems, we define the global and local reordering problems for distributed quantum computing. We formalise the mathematical problems and model them as integer linear programming problems, to minimise the number of SWAP gates or the number of interactions between different quantum computers. For global reordering, we analyse the problem for various geometries of networks: completely connected networks, general networks, linear arrays and grid-structured networks. For local reordering, in networks of quantum computers, we also define the mathematical optimisation problem

Optimising and recognising 2-stage delivery chains with time windows

In logistic delivery chains time windows are common. An arrival has to be in a certain time interval, at the expense of waiting time or penalties if the time limits are exceeded. This paper looks at the optimal placement of those time intervals in a specific case of a barge visiting two ports in sequence. For the second port a possible delay or penalty should be incorporated. Next, recognising these penalty structures in data is analysed to if see certain patterns in public travel data indicate that a certain dependency exists

Framework of synchromodal transportation problems

Though literature reviews of synchromodal transportation exist, no generalised mathematical model of these problems has been found yet. In this paper such a framework is introduced, by which mathematical models described in literature on synchromodal transportation problems can be classified. This framework should help researchers and developers to find solution methodologies that are commonly used in their problem instance and to grasp characteristics of the models and cases in a compact way, enabling easy classification, comparison and insight in complexity

A Multi Service Capacitated Facility Location Problem with Stochastic Demand

This paper considers the problem of identifying optimal locations for wireless service installations in smart cities. The problem is modelled as a facility location problem with multiple service types, known as the Multi Service Facility Location Problem (MSCFLP). Given a set of potential facility locations and demand point data, the goal is to identify at which locations the facilities should be opened, and which demand points should be serviced by each open facility in order to minimise costs. In this study, the demand quantities at each demand point are assumed to follow a probability distribution. An adaptive neighbourhood search heuristic is proposed in order to find a good solution to the problem, where the stochastic demand was translated to a deterministic capacity constraint. The heuristic iteratively improves the service allocations in sub-regions of the problem instances, starting from an initial feasible solution. The results show that the heuristic is able to find good solutions within very short time. Furthermore, we assessed the handling of the stochasticity by the model. Its performance is assessed by means of simulation, and results show that this approach works well in various scenarios of traffic models

Flexibility in Home Delivery by Enabling Time Window Changes

To enhance the perceived quality of home delivery services more and more flexibility is offered to the receivers. Enabling same-day delivery, communicating predefined narrow time windows, choosing the time windows and alternative address delivery add to the receiver’s experience, making the delivery company an interesting partner for parcel-shipping companies. A new flexibility is the possibility to change the chosen or communicated time window by the receiver during the day of delivery. In this paper we investigate the effect on delivery costs of this flexibility. Receivers are allowed to change their time window until the start of the old or new (the earliest) time window. In this paper two situations are investigated: one situation where communicated time window is a result of the planning process (Time Indication) and one situation where the original time window was already chosen by the receiver (Time choice). We show that the costs rises quickly in the Time Indication case when the percentage of time window changes grow. The Time Choice case is more costly at the start, but time window changes can be handled without (too much) extra costs. However, here a higher percentage of parcels is delivered outside the time windows

Optimising routing in an agent-centric synchromodal network with shared information

\u3cp\u3eOur research focuses on synchromodal planning problems in which information is shared between all agents in the system and they choose their routes based on an individual optimisation objective. We show the effect of the information availability by developing three different methods to determine the optimal paths, to motivate logistic players to cooperate in a synchromodal system.\u3c/p\u3