Approximating the Length of Vehicle Routing Problem Solutions Using Complementary Spatial Information

Accurately estimating the length of Vehicle Routing Problem (VRP) distances can inform transportation planning in a wide variety of delivery and service provision contexts. This study extends the work of previous research where multiple linear regression models were used to estimate the average distance of VRP solutions with various customer demands and capacity constraints. This research expands on that approach in two ways: first, the point patterns used in estimation have a wider range of customer clustering or dispersion values as measured by the Average Nearest Neighbor Index (ANNI) as opposed to just using a Poisson or random point process; second, the tour coefficient adjusted by this complementary spatial information is shown to exhibit statistically more accurate estimations. To generate a full range of ANNI values, point patterns were simulated using a Poisson process, a Matern clustering process, and a simple sequential inhibition process to obtain random, clustered, and dispersed point patterns, respectively. The coefficients of independent variables in the models were used to explain how the spatial distributions of customers influence the VRP distances. These results demonstrate that complementary spatial data can be used to improve operational results, a concept that could be applied more broadly.     

Discrete Element Modeling of Stone Masonry Walls With Varying Core Conditions: Prince of Wales Fort Case Study

The Prince of Wales Fort was constructed in the 18th century as a Vauban style stone masonry fortification where the Churchill River flows into Hudson’s Bay, across the river from Churchill, Manitoba, Canada. Since completion the fort has been exposed to harsh weather conditions, which have led to significant deterioration and deformations in the walls, with some cases of localized collapse. Recently, an increase in the rate of degradation has made preventative conservation an issue of interest. For this conservation to be possible, an understanding of the cause of failure of the walls is first required. Discrete element modeling (DEM) using the non-smooth contact dynamics (NSCD) method utilized in the Program LMGC90 has been used as a first step in understanding the failure mechanism of the wall system. The results of the modeling show that the rubble core of the walls can transition from stability to instability as the cohesion between the stones is altered. Grouting the core will alter the bond between stones, increasing the stability of the core, and is thus one possible conservation method.     

The <Emphasis Type="Italic">Trouvadore</Emphasis> Project: The Search for a Slave Ship and its Cultural Importance

Trouvadore was one of numerous illegal slave ships taking Africans from Africa after Britain had outlawed the slave trade in 1807. The vessel wrecked off the coast of East Caicos, Turks and Caicos Islands in 1841 and 168 of the survivors entered the local community, increasing the population by 7%. The Trouvadore Project, led by the Turks and Caicos National Museum, is uncovering the story of Trouvadore and the cultural legacy of the survivors. Bringing together many disciplines, including archaeology, this project provides information about Trouvadore for the present population of the Turks and Caicos, many of whom are direct descendants of the African survivors.