In this paper, we investigate a routing problem arising in the last-mile delivery of small packages. The problem, called Multi-Depot Vehicle Routing Problem with Private fleet and Common carriers (MDVRPPC), is an extension of the Multi-Depot Vehicle Routing Problem (MDVRP) where customers can either be served by the private fleet based at self-owned depots or by common carriers, i.e., subcontractors. We develop an effective Variable Neighborhood Search algorithm based on the use of cyclic-exchange neighborhoods that incorporates an adaptive mechanism to bias the random shaking step. The approach is successfully used to solve MDVRPPC as well as closely related problems, such as the MDVRP and the single-depot VRP with Private fleet and Common carriers (VRPPC), obtaining high quality solutions within short computing time. Our extensive testing on these problems shows the positive impact of the adaptive mechanism with respect to a standard VNS algorithm.

The exchange of cargo capacities is a well established approach in logistics. However, only few logistics marketplaces are able to take into consideration synergies that can be generated by combining different transportation routes of different logistics carrierps. In order to exploit these synergies, we designed and implemented the combinatorial exchange mechanism ComEx for the intra-enterprise exchange of delivery orders in a logistics company organized in a profit center structure. Each profit center is able to release delivery orders to an adjacent profit center if the geographic locations of the customers allow for a reduced-cost delivery by the adjacent profit center. We demonstrate that by using the ComEx mechanism, the total cost of transportation of our logistics company can be reduced by up to 14%. Since our iterative auction mechanism is very complex and therefore resourceintensive, we reduce the complexity by applying a convex hull approach combined with a distance-based cost estimator.

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Executive SummaryThe study of network topologies provides interesting insights into the way the principles on which the construction of connected systems are based influence diffusion dynamics and communication processes in many socio-technical systems.& Empirical research has shown that there are principles for the construction of social networks and their technical derivatives, like e-mail networks, the Internet, publication coauthoring, or business collaboration. & Such real world networks attach new members over time and the mode of attachment prefers existing members that are already well connected. This principle is called "preferential attachment" and leads to the emergence of "scale-free" networks. & Scale-free networks seem to be a better fit for the description of real world networks than the random networks used so far. Their behavior in terms of diffusion and communication processes is fundamentally different from that of random networks. & To illustrate the value of scale-free networks for applications in information systems re-search, examples will be given to illustrate their usefulness for real world network modeling. A communication network of security traders will show what impact network topology has on the dynamics of complex socio-technical systems.

This letter analyzes the intrinsic optical switching response of state-of-the-art high power, multiquantum wells, thinfilm, and surface-textured infrared light emitting diodes (LEDs). For the switching time response of such devices, the theoretical basics are presented and their predictions are experimentally verified. In the second part of this letter, a novel, fast switching LED driving circuit is presented which enables nanosecond-pulse operation. The circuit reduces significantly the optical rise and fall time of LEDs from 10/15 ns, respectively, down to 2.6 ns at 2-A pulse current without compromising the peak output power.