Maximum Coverage and Maximum Connected Covering in Social Networks with Partial Topology Information

Viral marketing campaigns seek to recruit the most influential individuals to cover the largest target audience. This can be modeled as the well-studied maximum coverage problem. There is a related problem when the recruited nodes are connected. It is called the maximum connected cover problem. This problem ensures a strong coordination between the influential nodes which are the backbone of the marketing campaign. In this work, we are interested on both of these problems. Most of the related literature assumes knowledge about the topology of the network. Even in that case, the problem is known to be NP-hard. In this work, we propose heuristics to the maximum connected cover problem and the maximum coverage problem with different knowledge levels about the topology of the network. We quantify the difference between these heuristics and the local and global greedy algorithms

A dynamic ridesharing dispatch and idle vehicle repositioning strategy with integrated transit transfers

We propose a ridesharing strategy with integrated transit in which a private on-demand mobility service operator may drop off a passenger directly door-to-door, commit to dropping them at a transit station or picking up from a transit station, or to both pickup and drop off at two different stations with different vehicles. We study the effectiveness of online solution algorithms for this proposed strategy. Queueing-theoretic vehicle dispatch and idle vehicle relocation algorithms are customized for the problem. Several experiments are conducted first with a synthetic instance to design and test the effectiveness of this integrated solution method, the influence of different model parameters, and measure the benefit of such cooperation. Results suggest that rideshare vehicle travel time can drop by 40-60% consistently while passenger journey times can be reduced by 50-60% when demand is high. A case study of Long Island commuters to New York City (NYC) suggests having the proposed operating strategy can substantially cut user journey times and operating costs by up to 54% and 60% each for a range of 10-30 taxis initiated per zone. This result shows that there are settings where such service is highly warranted

Evolution of the Second-Story City: The Minneapolis Skyway System

This paper describes and explains the growth of the Minneapolis Skyway network. Accessibility is used as a major factor in understanding that growth (i.e. does the network connect to the location(s) with the highest accessibility, followed by the second highest, and so on). First, employment opportunities are used as the measure of activity and are based off of the square footage of buildings and/or ITE trip generation rates. Using information about the buildings located downtown for each year since the first skyway was built, the accessibilities of each of the connected and adjacent unconnected blocks were calculated for every time period the skyway system expanded. The purpose is to determine how often the expansion connected the block with the highest accessibility. The results show that though important, accessibility was rarely maximized, except in the early stages of development. A connect-choice logit model relating the probability of joining the network (in a given year) to accessibility and network size was employed. The results show accessibility does remain an important factor in predicting which links are connected. Physical difficulties in making connections may have played a role, as well as the potential for adverse economic impacts.Network growth, Transport economics, Incremental connection, Skyways, Minneapolis