Optimization of Urban Multi-project Infrastructure Renovation Scheduling
Robbert Bosch
Ph.D. Candidate, IEBIS Department, University of Twente
In this presentation, we address the integrated problem of scheduling renovation projects and corresponding construction transport, with a focus on the renovation of bridges and quay walls. Over time, these pieces of infrastructure need to be replaced. Such renovation projects have a large impact on local traffic; each project generates construction traffic and often temporarily disables local roads and waterways, disrupting both road- and water-based traffic in the surrounding area. Scheduling of renovation projects needs to minimize project lateness to avoid dangerous situations due to neglected infrastructure, while avoiding excessive congestion due to parallel renovation projects being executed, as that leads to increased emissions and time loss for traffic participants. Additionally, constraints with respect to resources (such as material and equipment) and availability of transport routes for these resources have to be accounted for.
We formulate the problem as a bi-level optimization problem. The upper level consists of the resource-constrained multi-project scheduling problem (RCMPSP) with transport mode choice for resources. The goal is to minimize the total lateness of projects and minimize the increase in travel time on the local road- and canal traffic network. At the lower level, the distribution of traffic in the networks is determined using the adjusted traffic networks that result from ongoing renovation projects as input. The distribution of traffic on the networks and the resulting travel time is determined using a Traffic Assignment Problem (TAP). Additionally, the accessibility of renovation projects is determined at the lower level, using the same adjusted traffic networks as input. The goal of the lower level is for road users to minimize their travel time, and to determine accessibility of projects for each resource.
To solve the upper level problem, we use a multi-objective Genetic Algorithm (GA) called NSGA-II. NSGA-II generates a partial Pareto front of solutions that quantifies trade-offs between project lateness and travel time delay. We provide insight into the performance of NSGA-II on an integrated scheduling and transport planning problem and on the trade-off between project lateness and traffic congestion.
Robbert is a PhD candidate at IEBIS from the Netherlands. He grew up in Almere and studied IEM at the University of Twente, with a specialization in supply chain management and transport management. In his spare time, he likes to cook, do gardening, and bouldering.
Measuring Security in Cloud Outsourcing
MUHAMMAD YASIR MUZAYAN HAQ
Ph.D. Candidate, IEBIS Department, University of Twente
Over the past decade, the trend in both the public sector and industry has been to outsource ICT to the cloud for economic, performance, and security reasons. Cloud providers utilize redundant and distributed network infrastructures which are arguably more resilient against cyber and physical attacks. However, several incidents in the past, due to either malicious activity or misconfiguration, showed that the cloud is not immune to disruptions. The impact of the cloud disruptions on Internet users is even larger due to centralization in the cloud market: a few giant providers dominate the market of B2B Cloud services leading to massive cascading effects. In this project, we investigate the resilience of the cloud outsourcing ecosystem by evaluating the decisions made by cloud consumers and the impact of cloud centralization on the resilience of the Internet.
Yasir is a Ph.D. candidate at IEBIS from Indonesia with a research focus on the economics of cloud security using Internet measurement data. He pursued his master's degree from the University of Twente, in the Business and IT program. Before starting his doctoral, he worked as a business analyst and data scientist at several companies in Indonesia, in the financial and big data industries. During his spare time, he loves watching movies and having a road trip with his family. He lives in Enschede with his wife and two sons.