Download or read book Neues verkehrswissenschaftliches Journal Ausgabe 22 written by Weiting Zhao and published by BoD – Books on Demand. This book was released on 2018-01-23 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the increasing traffic demand and limited infrastructure expansion, railway operation becomes more susceptible to the operational disturbances. In order to ensure a robust railway operation, a proactive dispatching algorithm in dynamic circumstances under the consideration of random disturbances is necessary. In this study, an operational risk map will be firstly produced: by simulating considerable amount of disturbed scenarios generated in a Monte-Carlo scheme and calculating the corresponding expected negative impacts, different levels of operational risk will be assigned to each block section in the investigated network. Within a rolling time horizon framework, conflicts are detected with the inclusion of risk-oriented disturbances in each block section, and the near-optimal dispatching solutions are calculated by using Tabu search algorithm. Finally, three indicators including total weighted waiting time, the number of relative reordering and average absolute retiming, are chosen to testify the effectiveness and advantages of the proposed dispatching algorithm. The sensitivity analysis of dispatching-related parameters is conducted afterwards to investigate the most appropriate relevant parameters for the specific studied area. The proposed algorithms are expected to be capable of automatically producing near-optimal and robust dispatching solutions with sufficient punctuality achieved.
Download or read book Neues verkehrswissenschaftliches Journal Ausgabe 19 written by Di Liu and published by BoD – Books on Demand. This book was released on 2017-07-11 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rail-bound transport in urban areas plays an important role in public transport. Given its urban setting, urban rail-bound transport can be significantly influenced by the interfering road traffic around it. Considering the capacity and operation quality of urban rail-bound transport influenced by road traffic in various urban mixed traffic zones, it'very important to investigate and include the road traffic influences for capacity research on urban rail-bound transport. In this dissertation, two approaches are developed to model the road traffic influences according to the analysis of the interactions between urban mixed traffic in various mixed traffic zones. As an important intermediate result, the newly-developed waiting time function is determined to adapt to an urban rail-bound system with consideration of external influences. Furthermore, an algorithm is developed in the model with an event-driven system to simulate the interactions among urban mixed traffic in various mixed traffic zones. This algorithm is used to assess the significance of mixed traffic impacts and derive the primary results for capacity research.
Download or read book Neues verkehrswissenschaftliches Journal Ausgabe 18 written by Jiajian Liang and published by BoD – Books on Demand. This book was released on 2017-08-18 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: A railway system is a complex system. With the assistance of a railway operation control system, railway traffic is managed according to an operation plan. During the operation process, especially in railway networks with complex topology and high traffic flow, disturbances are likely to occur, which may result in severe deviations of train movements from the pre-designed operation plan. Once conflicts have occurred or potential conflicts between trains have been detected, suitable dispatching actions should be executed to minimize the negative impacts of the disturbances. In order to support dispatchers, a dispatching optimization algorithm was developed in this dissertation. In the development of dispatching models, two aspects need be considered: modelling of railway operation and the dispatching optimization algorithm. The former is indispensable to accurately assess the impact of disturbances, and the latter is employed to find solutions with minimal impact. In order to balance accuracy and computation complexity a multi-scale simulation model was developed in this dissertation. Dispatching optimization is a typical combinatorial optimization problem, and exhaustive search becomes impractical when there is a large set of possible dispatching solutions. To speed up the search, a widely used metaheuristic algorithm-tabu search - was adopted as the basis of the dispatching optimization algorithm. This dissertation addressed both multi-scale simulation and dispatching optimization in railway operation.
Download or read book Neues verkehrswissenschaftliches Journal Ausgabe 26 written by Yong Cui and published by BoD – Books on Demand. This book was released on 2018-10-25 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: Simulation methods are widely-used in the field of railway planning and operations. 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 book 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 user-adaptable open interfaces.
Download or read book Neues verkehrswissenschaftliches Journal NVJ Ausgabe 4 written by Yong Cui and published by BoD – Books on Demand. This book was released on 2010 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Neues verkehrswissenschaftliches Journal written by Verkehrswissenschaftliches Institut (Stuttgart) and published by . This book was released on 19?? with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Neues verkehrswissenschaftliches Journal written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Neues Verkehrswissenschaftliches Journal Ausgabe 19 written by Di Liu and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Neues verkehrswissenschaftliches Journal NVJ Ausgabe 7 written by Ullrich Martin and published by BoD – Books on Demand. This book was released on 2014-03-14 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: Leistungsuntersuchungen im spurgeführten Verkehr spielen bei der Planung der Infrastruktur sowie des Betriebsprogramms und beim Vergleich verschiedener Dispositionsmaßnahmen eine wichtige Rolle und stellen einen Bezug zur Betriebsqualität her. Der als Ergebnis von Leistungsuntersuchungen bestimmte optimale Leistungsbereich beschreibt als wichtige globale Kenngröße das Intervall, in dem die Leistungsanforderungen einer ausreichenden Wirtschaftlichkeit und einer hinreichenden Qualität entsprechen. Die stetige Wartezeitfunktion sowie die zu deren Bestimmung notwendige maximale Leistungsfähigkeit die sind zwei grundlegende Voraussetzungen zur Bestimmung des optimalen Leistungsbereichs. Mit den in dieser Arbeit neu entwickelten Methoden und den daraus abgeleiteten Algorithmen werden die bisherigen Ansätze zur Approximation der Wartezeitfunktion aus einzelnen Datenpunkten systematisch algorithmisch weiterentwickelt und in der Folge die Aussagekraft des optimalen Leistungsbereichs signifikant verbessert.
Download or read book Neues verkehrswissenschaftliches Journal Ausgabe 24 written by Nan Cao and published by BoD – Books on Demand. This book was released on 2018-01-31 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: An efficient utilization of existing infrastructure can be achieved with a more efficient operation. However, the occupancy of infrastructure has not been discussed in the existing definitions and evaluation methods of homogeneity. An extension of existing definitions is presented from the perspective of the infrastructure, which can be characterized by variations in blocking time, buffer time and running direction. The blocking time, buffer time and running direction describe the occupancy of train path on track sections based on the blocking time model. Accordingly, the homogeneity of operating programs is evaluated through three parameters, namely the homogeneity of blocking time (HBL), the homogeneity of buffer time (HBU) and the homogeneity of running direction (HRD). The overall homogeneity (OH) combined these three parameters to realize an integrity evaluation of homogeneity of operating programs. This new methodology can quantify the homogeneity of railway operations, not only for track sections but for an entire network, which contributes significantly to the efficient utilization of infrastructure. In addition, the interrelationship between homogeneity of operating programs and operation quality were investigated quantitatively for both each parameter of homogeneity and the overall homogeneity. The operation quality deteriorates with less homogeneous timetables, in which the variation in buffer time has a more significant influence. Finally, the influence of homogeneity of operating programs in capacity research is studied for different scenarios. The low traffic flow is more sensitive to the homogeneity of buffer time and the homogeneity of blocking time is more significant for high traffic flow.
Download or read book Neues verkehrswissenschaftliches Journal Ausgabe 16 written by Ullrich Martin and published by BoD – Books on Demand. This book was released on 2017-03-09 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: In urban mixed traffic zones, urban rail-bound transport interacts with road traffic, which includes motorized road traffic as well as non-motorized road traffic. The quality of operation and the capacity of urban rail-bound transport are heavily influenced by the road traffic in urban mixed traffic zones. Capacity research is one of the most important methods for the validation of timetables on an existing or planned infrastructure, for adequate railway capacity design of the infrastructure, as well as the performance evaluation for railway operation. For the urban mixed traffic zones, two developed approaches in this research can be used to carry out capacity research with consideration of the road traffic influences on urban rail-bound transport. As a result of the stochastic influences of road traffic on urban rail-bound transport, the waiting time function will be adapted to mixed traffic conditions, which can derive the recommended area of traffic flow for the situation of urban mixed traffic more plausibly. In addition, an algorithm for modeling an event-driven system is developed for preliminary determining the results of capacity research. Accordingly, the operating performance for urban rail-bound transport with road traffic influences can be determined and evaluated.
Download or read book Neues verkehrswissenschaftliches Journal Ausgabe 20 written by Ullrich Martin and published by Books on Demand. This book was released on 2017-08-15 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: Capacity research is applied to describe the relationship between capacity and operation quality within a defined investigated area of a certain infrastructure network. When simulation methods are used in capacity research, the integrated dispatching modules will influence the final results of capacity research. In the worst case scenario with a large number of trains, an unsuitable dispatching algorithm perhaps cannot realize the timetabled capacity, which underlines the importance of choosing suitable dispatching algorithms for the target capacity. In order to evaluate these influences, a new state-dependent dispatching algorithm, which can be adjusted according to the system states, was designed, and a classification method of system states was developed. In the further dispatching process, the system states should be identified primarily, and the most suitable dispatching algorithm can be automatically carried out. Moreover, a multi-scale simulation model characterized by continuous scaling was built to calculate the waiting times based on timetables with stochastic deviations. With the simulation method, the influence of dispatching on the results of capacity research was systematically investigated, and convincing results were eventually produced.
Download or read book Track Data Oriented Maintenance Intervention Limit Determination for Ballasted Light Rail Tracks through Multibody Simulations written by David Camacho Alcocer and published by BoD – Books on Demand. This book was released on 2021-07-13 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: Light rail trains (LRT) are an important part of public transport but due to perceived high life-cycle costs are not always considered suitable. Life cycle cost reduction might be achieved through a knowledge-based maintenance management rather than just on experience. This work develops limits of maintenance and renewal of LRT systems based on vehicle reactions to the current track quality through measured data, multibody simulations and track geometry indices. An approach based on knowledge would lead to a track condition which allows a safe, comfortable, and under an appropriate maintenance strategy, economically profitable operation.
Download or read book Investigation of Form Effect on Ballast Mechanical Behavior Based on Discrete Element Modeling written by Bo Wang and published by BoD – Books on Demand. This book was released on 2019-08-27 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: As an essential component of the ballast track, the ballast layer provides functionali-ties such as drainage, load distribution, as well as strength and stability for the rail-way track. The mechanical behaviors of ballast track such as its permanent settle-ment, breakage, force propagation and void ratio are in a great extent influenced by the form distribution of ballast stones. Its reasonable design will greatly improve the mechanical behaviors, and thus prolong the maintenance cycle of ballast track, or reduce the number of ballast stones needed for construction. This dissertation focuses on proposing optimized ballast stones in the ballast aggre-gate in regard to their geometrical forms. As the first step, a ballast random form gen-erator, which is designed to generate ballast form databases with different form dis-tributions, is proposed. 15 databases are created for further usage. Afterwards, Dis-crete Element Method (DEM) based simulations are performed to investigate the mechanical behaviors of ballast aggregates. The simulation model is established based on a box test, whose result is presented firstly. Establishment and calibration process of the model are expatiated afterwards. A parameter study regarding to cru-cial modeling parameters is also performed. Using the validated parameters and the 15 generated form databases, DEM simulation models with different form distribu-tions of ballast stones in the ballast aggregate are proposed. Simulative methods to quantify the mechanical behaviors are elaborated. Based on the obtained results, the interrelation between mechanical behaviors of ballast aggregate and the form effect on mechanical behavior of the ballast aggregates are studied. The optimized ballast aggregate is proposed based on the findings stated above. The proposed optimized ballast aggregate is expected to be a reference for construc-tion of ballast track in real world. The modeling technic and the calibrated modeling parameters can be used for optimization for different railway operating programs.
Download or read book NEUES VERKEHRSWISSENSCHAFTLICHES JOURNAL AUSGABE 15 written by ULLRICH. HERZWURM MARTIN (GEORG. CAMACHO ALCOCER, DAVID.) and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optimization of Schedules with Heterogeneous Train Structure in Plan ning of Railway Lines written by Hyoung June Kim and published by BoD – Books on Demand. This book was released on 2020-06-23 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the most important things to consider before constructing a railway is the train operating program. However, the analysis of the operating program based train schedule in the railway planning stage is carried out mainly on the basis of the intuitive experiences of the planner, and the optimization of the train schedule under various conditions is not properly considered. This study analyzes the optimization of heterogeneous train scheduling structures with minimizing the weighted scheduled waiting time and with the decision of Subsidiary Main Track (SMT) for overtaking of high-speed trains on the railway line. As a way for analyzing the Optimal Train Schedule (OTS) under constraint conditions, the genetic algorithm is used. The genetic algorithm is widely applied to various optimization and decision-making problems in engineering, natural sciences, business administration, and social sciences. The proposed method can examine train schedules for more scenarios, apply quantitative evaluation criteria, and review concrete infrastructures in comparison to the existing empirical method used in South Korea.
Download or read book Public Sector Reform written by Jan-Erik Lane and published by SAGE. This book was released on 1997-12-12 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: Deregulation, privatization and marketization have become the bywords for the reforms and debates surrounding the public sector. This major book is unique in its comparative analysis of the reform experience in Western and Eastern Europe, Australia, New Zealand and Canada. Leading experts identify a number of key factors to systematically explain the similarities and differences, map common problems and together reflect on the future shape of the public sector, exploring significant themes in a lively and accessible way.
