Synchronization in hub terminals with the circular arrangement problem

Hub terminals are important entities in modern distribution networks and exist for any transportation device, that is, cross docks and parcel distribution centers for trucks, container ports for ships, railway yards for trains, and hub airports for aircraft. In any of these hubs, the mid‐term planning task of synchronizing the transshipment of goods and passengers when servicing the transportation devices has to be solved, for which many different solution approaches specifically tailored to the respective application exist. We, however, take a unified view on synchronization in hubs and aim at a general building block. As a point of origin, a basic vertex ordering problem, the circular arrangement problem (CAP), is identified. We explain the relation between the CAP and hub processes, develop suited algorithms for solving the CAP, and extend the basic CAP by multiple additions, for example, arrival times, limited storage space, and multiple service points, make the problem adaptable to a wide range of hub terminals. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 454–469, 2015     

The Scope of Foreign Assistance to North Korea’s Missile Program

There is evidence that North Korea’s ballistic missile program benefited from support from the Soviet Union until its collapse and from Russia thereafter. Along with transfers of missile systems and rocket components, it appears that Russian engineers directly supported the program in North Korea. Analysis of missile launches, imagery, design solutions, and technology suggest that Pyongyang’s recent missile program may have continued to have external support despite a pause in the 2000s. This assistance may have enabled the progress in North Korea’s missile program leading to tests of an intercontinental range ballistic missile in 2017.