It is expected to enhance the possibilities for improving solutions later in the recreate phase. Exploiting PDSVRP solution characteristics in an effective manner, our heuristic manages to introduce “sufficient” rooms to a solution via new removal operators during the ruin phase. We formulate the problem as a Mixed Integer Linear Program and then develop a Ruin and Recreate (R&R) algorithm. This problem is a variant of the well-known Parallel Drone Scheduling Traveling Salesman Problem (PDSTSP) recently introduced in the literature in which we allow multiple trucks and consider the objective of minimizing the total transportation costs. In this paper, we introduce a new optimization problem called the min-cost Parallel Drone Scheduling Vehicle Routing Problem (PDSVRP). Indeed, depending on the energy consumption coefficients of trucks and drones as well as on the distance covered by drones, the mTSP-DS can also achieve energy savings in comparison to mTSP solutions.Īdopting unmanned aerial vehicles (UAV), also known as drones, into the last-mile-delivery sector and having them work alongside trucks with the aim of improving service quality and reducing the transportation cost gives rise to a new class of Vehicle Routing Problems (VRPs). Furthermore, we investigated the energy consumption of trucks and drones. According to the numerical results, we observe that the use of drone stations leads to considerable savings in delivery time compared to traditional mTSP solutions. To verify the performance of our algorithms, we conducted extensive computational experiments.
Afterwards, we suggest a third approach that is based on populating a solution pool with several restarts of an iterated local search metaheuristic, which is followed by determining the best combination of tours using a set-partitioning model. To address larger instances, we first introduce two variants of a decomposition-based matheuristic. We formulate the mTSP-DS as a mixed integer linear programming (MILP) model to solve small instances. The goal is to serve all customers either by truck or by drones/robots while minimizing the makespan. The trucks start their mission from the depot and can supply some packet stations, which can then launch and operate drones/robots to serve customers. In the mTSP-DS, we have a depot, a set of trucks, and some packet stations that host a given number of autonomous vehicles (drones or robots).
#Drone station 2015 pro
While US drone strikes have become far rarer in recent years, the relationship between Washington and Islamabad has also improved dramatically, with Pakistan lodging only pro forma protests when drone strikes do take place.In this paper, we introduce the multiple Traveling Salesman Problem with Drone Stations (mTSP-DS), which is an extension to the classical multiple Traveling Salesman Problem (mTSP). The issue of drone strikes has faded from public concern in Pakistan in recent years and is nothing like as prominent as it was in 2009, when the CIA campaign was running at a high tempo. With no chance of either of the two Americans travelling to Pakistan to face their day in court, the case is unlikely to go anywhere. Press reports at the time suggested the target of the strike was the then-Taliban commander for North Waziristan, a militant called Haji Omar. The CIA never comments on an officially secret programme, and independent investigators face hurdles trying to work in North Waziristan, an area that for years was under the control of militant groups.
There are few hard facts about the 2009 drone strike. Many assumed Pakistan’s own spies leaked the name to punish the CIA at a time of fraught ties with the US.
The extraordinary unmasking of a sitting station chief forced Banks to quit his post and leave the country.īanks went on to become the head of the Iran operations divisions at the CIA’s headquarters and currently works in the US military’s intelligence wing.Īt the time, the outing of Banks sparked much speculation about how Khan and his lawyer Shahzad Akbar could possibly have known the identity of the CIA station chief. Justice Shaukat Aziz Siddiqui of the Islamabad high court also ruled charges should be brought against John A Rizzo, formerly the top CIA lawyer who gave the legal green light for drone strikes.īanks’s name was first dragged into the public domain in 2010 when a tribesman called Karim Khan began legal action against the supposedly undercover spy chief over an attack by an unmanned aircraft on his home in North Waziristan which he said killed his brother and son.
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