02 Fakultät Bau- und Umweltingenieurwissenschaften

Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/3

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Institute: search.filters.UBSInstitut.Institut für Eisenbahn- und VerkehrswesenAuthor: search.filters.author.Cui, Yong

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Now showing 1 - 3 of 3
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    Probabilistic analysis of crack growth in railway axles using a Gaussian process
    (2020) He, Jiajie; Cui, Yong; Liu, Yusun; Wang, Hui
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    PULSim: user-based adaptable simulation tool for railway planning and operations
    (2018) Cui, Yong; Martin, Ullrich; Liang, Jiajian
    Simulation methods are widely used in the field of railway planning and operations. Currently, several commercial software tools are available that not only provide functionality for railway simulation but also enable further evaluation and optimisation of thenetwork for scheduling, dispatching, and capacity research. However, the various tools are all lacking with respect to the standards they utilise as well as their published interfaces. For an end-user, the basic mechanism and the assumptions built into a simulation tool are unknown, which means that the true potential of these software tools is limited. One of the most critical issues is the lack of the ability of users to define a sophisticated workflow, integrated in several rounds of simulation with adjustable parameters and settings. This paper develops and describes a user-based, customisable platform. As the preconditions of the platform, the design aspects for modelling the components of a railway system and building the workflow of railway simulation are elaborated in detail. Based on the model and the workflow, an integrated simulation platform with open interfaces is developed. Users and researchers gain the ability to rapidly develop their own algorithms, supported by the tailored simulation process in a flexible manner. The productivity of using simulation tools for further evaluation and optimisation will be significantly improved through the useradaptable open interfaces.
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    Simulation based hybrid model for a partially automatic dispatching of railway operation
    (2010) Cui, Yong; Martin, Ullrich (Prof. Dr.-Ing.)
    The efficiency and service quality in railway operation can be improved with the support of a partially-automatic dispatching system. Three types of automatic dispatching system model are prevailing: simulative, analytical, and heuristic. However, none of them is able to reconcile the different preferences between system performance and the quality of dispatching solutions individually. A hybrid model is therefore designed in this dissertation. In the hybrid model, the synchronous simulation is utilized as a basis in order to generate a basic dispatching solution. This dissertation focuses on the components and the workflow of a synchronous simulation and addresses the deadlock problem during a synchronous simulation. Deadlock avoidance can be achieved by the Banker's algorithm and the associated improvements, which are designed to prevent trains from unnecessarily stopping and to improve system performance. The implementation shows that the synchronous simulation can reschedule train movements reliably, and the Banker's algorithm can deal with deadlock problems even for very complex train movements (e.g. shunting movements). In a simulative dispatching mode, the calculated train priority parameters are utilized in requesting infrastructure resources, allocating infrastructure resources, or both. After a basic dispatching solution has been generated, further optimization can be carried out on a macroscopic level, and then be elaborated on a microscopic level. Several different optimization techniques, including Tabu search and Linear Pro-gramming, can be utilized in such a multi-level dispatching and optimization frame-work. Finally, an optimized dispatching solution will be developed with consideration to the balance of system performance and dispatching solution quality using a simulation-based hybrid model. In this dissertation, the framework of a hybrid model for a partially-automatic dis-patching of railway operation is proposed. A synchronous simulation model is implemented in the work of the dissertation as the basis, from which further implementation can be designed and be developed continuously.