Periodic train timetable expansion: An integrated model of multi-period train service selection and rolling stock circulation with time-varying passenger demand

The periodic train timetable is one of the most widely used train timetables in passenger railway systems worldwide. However, how to expand well-coordinated daily train services from a single-period timetable pattern is rarely studied. This paper develops a multi-objective mixed integer programming model to solve the periodic train timetable...

Integrated optimization of timetable, bus formation, and vehicle scheduling in autonomous modular public transport systems

This paper presents a joint optimization of the timetable, bus formation, and vehicle scheduling in a flexible public transport (PT) system that utilizes autonomous modular vehicles (AMVs). In this system, AMVs have the capability to detach or join with each other at intermediate stops along the route to dynamically adjust the bus formation ...

Optimization-based strut-and-tie model generation for reinforced concrete structures under multiple load conditions

Strut-and-Tie modelling (STM) has been widely applied to design D-regions of reinforced concrete structures. For economic and environmental reasons there is a need for optimized Strut-and-Tie models. How to optimize Strut-and-Tie models considering multiple load combinations has not been investigated extensively in the literature. In order to...

Towards a systematic design approach of D-regions in reinforced concrete: Optimization-based generation of Strut-and-Tie models

Reinforced Concrete (RC) structures are widely used in our society for more than a century. In order to design safe and economical RC structures, various methods have been proposed by engineers and researchers. Remarkably, it still is a challenging task for engineers to design D-regions of RC structures, regions with nonlinear strain...

Automated optimization-based generation and quantitative evaluation of Strut-and-Tie models

Strut-and-Tie modelling (STM) is a well-known approach to design D-regions in reinforced concrete structures. Because the STM method is based on lower-bound analysis, finding a suitable truss-analogy model is the most important aspect to guarantee good structural and economic performance of a resulting design. Continuum topology optimization ...

Simultaneous optimization of shape and topology of free-form shells based on uniform parameterization model

In current optimization methods for free-form shells, the shape and topology are usually optimized separately. These methods are based on the assumption that the shape and topology of a shell influence each other only slightly, but this is not always correct. Moreover, different parameterization models are used in the shape optimization and...

Integration of real-time traffic management and train control for rail networks: Part 1: Optimization problems and solution approaches

We study the integration of real-time traffic management and train control by using mixed-integer nonlinear programming (MINLP) and mixed-integer linear programming (MILP) approaches. Three innovative integrated optimization approaches for real-time traffic management that inherently include train control are developed to deliver both a train...

Integration of real-time traffic management and train control for rail networks: Part 2: Extensions towards energy-efficient train operations

We study the integration of real-time traffic management and train control by using mixed-integer nonlinear programming (MINLP) and mixed-integer linear programming (MILP) approaches. In Part 1 of the paper (Luan et al., 2018), three integrated optimization problems, namely the P_NLP problem (NLP: nonlinear programming), the P<sub...

Support Structure Optimization: On the use of load estimations for time efficient optimization of monopile support structures of offshore wind turbines

Over the years, the installed capacity of offshore wind turbines is increasing rapidly. However, the Levelized Costs Of Energy (LCOE) is still higher than the LCOE of traditional energy production methods like nuclear power or energy from coals or gas. This research focuses on a further decrease of the LCOE, by minimizing the mass of a monopile...

Controller-structure optimization using parameter-dependent modal reduced state-space models

Although it is still common in the field of motion control systems to first design the structure and then the controller, integrated design approaches are becoming more popular. The problem of finding optimal parameters for a parameterized structure and controller by solving an optimization problem will be referred to as \textit{controller...