Line Planning Research Articles

Management of border zone forests of transmission line corridors

The resilience of power transmission has been required in Finland by the electricity market act since 2013. As a consequence, Finnish electricity companies began to manage border zone forests of transmission lines more extensively. Five years later, the experiences of experts representing different interest groups in border zone forest management projects along medium-voltage (MV) and high-voltage (HV) transmission lines were summed and analysed in this study utilising argument Delphi method. The first-round interview included 13 experts, and the second-round survey 33 experts representing electricity companies, forest management associations, forest companies and forest machine operators.
 According to the results, landowners’ knowledge of border zone forest management should be increased by video clips linked to electricity companies’ web-pages, project-specific work demonstrations and demonstrations in exhibitions and other events. Increased knowledge and activation of landowners is crucial when a new MV transmission line corridor is being built. This could offer cost-efficient possibilities to extend joint harvestings in the vicinity forests.
 Planning of border zone forest operations and marking estate borders, border zone forests and dangerous spots were found helpful and increase the safety and productivity of harvesting operators. Harvestings by cut-to-length harvesters in the vicinity of transmission lines require calm and experienced harvester operators.
 According to the experts, on MV transmission lines, the corridor should be utilised in harvesting operation if possible. If a strip road is needed, it should be placed next to the transmission line corridor, enabling felling away from the transmission line. In HV transmission line border forest operations, the closest strip road to transmission line should be placed on the border zone. Strip road planning of individual thinning nearby transmission lines should consider the need for strip road in the border zone as well.
 As a conclusion, information exchange between interest groups of border zone forest management projects and guidance for landowners is crucial for successful border zone forest management projects and needs to be further enhanced.

Weather Impact on Passenger Flow of Rail Transit Lines

Passenger flow prediction is important for the planning, design and decision-making of urban rail transit lines. Weather is an important factor that affects the passenger flow of rail transit line by changing the travel mode choice of urban residents. A number of previous researches focused on analyzing the effects of weather (e.g. rain, snow, and temperature) on public transport ridership, but the effects on rail transit line yet remain largely unexplored This study aims to explore the influence of weather on ridership of urban rail transit lines, taking Chengdu rail transit line 1 and line 2 as examples. Linear regression method was used to develop models for estimating the daily passenger flow of different rail transit lines under different weather conditions. The results show that for Chengdu rail transit line 1, the daily ridership rate of rail transit increases with increasing temperature. While, for Chengdu rail transit line 2, the daily ridership rate of rail transit decreases with increasing wind power. The research findings can provide effective strategies to rail transit operators to deal with the fluctuation in daily passenger flow.

Timetabling for Strategic Passenger Railway Planning

In research and practice, public transportation planning is executed in a series of steps, which are often divided into the strategic, the tactical, and the operational planning phase. Timetables are normally designed in the tactical phase, taking into account a given line plan, safety restrictions arising from infrastructural constraints, as well as regularity requirements and bounds on transfer times. In this paper, however, we propose a timetabling approach that is aimed at decision making in the strategic phase of public transportation planning and to determine an outline of a timetable that is good from the passengers’ perspective. Instead of including explicit synchronization constraints between train runs (as most timetabling models do), we include the adaption time (waiting time at the origin station) in the objective function to ensure regular connections between passengers’ origins and destinations. We model the problem as a mixed integer quadratic program and linearise it. Furthermore we propose a heuristic to generate starting solutions. We illustrate the type of solutions found by our approach on two case studies based on the Dutch railway network and analyse trade-offs that are made to balance dwell times and regularity of trains.

Optimization of High-Speed Railway Line Planning Considering Extra-Long Distance Transportation

Network line planning optimal considering extra-long distance transportation can adapt to high-speed railway (HSR) network operation environment and meet the demand of extra-long distance travel. First, the distance of 1500 km or more is defined as extra-long transportation distance based on market competitiveness. The difficulties of direct or transfer transportation for extra-long distance transportation are analyzed. Direct method of extra-long distance is determined according to direct passenger volume and the number of important nodes while transfer method is represented considering transfer times, organization forms, varieties of schemes, and comfort. Then, ideas of optimizing line plan based on riding scheme is put forward. Network optimizing line plan model with riding scheme is developed considering extra-long distance transportation. The model which minimizes traveling cost and train running expense optimizes train frequency and train stop plan with riding scheme. Last, the method and optimizing model is verified by the network which took Baoji–Lanzhou HSR as the core. The optimal result is a benefit to improve operation efficiency and market competitiveness of HSR.

Method for Determining the Valid Travel Route of Railways Based on Generalised Cost under the Syncretic Railway Network

Travel route options for passengers can provide data support for railway line planning, passenger flow organisation, and train operation establishment. A critical review of the literature indicates that previous studies mainly focused on choices offered by a single railway network path without much consideration of China’s normal-speed and high-speed integrated railway network and the effect of train timetable on passengers’ travel choice. In this study, a method based on generalised cost is proposed to discover the valid routes of passenger travel in the integrated network of China’s normal-speed and high-speed railways. After quantifying the effects of train fare, travel time, transfer, travel convenience, comfort, and other factors on the generalised expenses of passengers, this study presents a generalised cost determination method when individuals select an option from different seats of different trains of specific railway transport products. Theoretically, the valid routes considering the train schedule is defined, and a valid route search algorithm is designed using the deep traversal idea in a new valid route searching network. Considering the Lanzhou-Beijing passenger travel routes as an example, this study verifies the practicability of the generalised cost calculation method, as well as that of the valid routes search method.

Line planning and passenger routing problem with application to the Quito transportation system.

An important phase in the strategic planning process of a public transportation system is the line planning problem. It consists in determining a set of lines together with their frequencies such that a given transportation demand is satisfied. In this work an integer programming model for the integrated line planning and passenger routing problem is proposed. The model aims to improve the benefit and comfort of the passengers, namely maximising direct connection trips, and it also proposes to minimise the total cost for the operator. Restricted to linear transportation networks that are relevant for the Quito public transportation system, NP-hardness results and polynomial algorithms for special cases are presented. Performance of heuristic procedures for solving the integrated problem is evaluated over real-world and simulated instances.

A line planning approach based on harmony search for high-speed rail: From the perspective of service accessibility

Service accessibility can be used to describe the travel time of passengers between different nodes, and opportunities to get transportation services in the high-speed railway (HSR) system. Based on the traditional train line planning theory, this paper introduces the transportation service accessibility index, and propose a new nonlinear passenger train line planning model, which aims to maximize the service accessibility, as well as minimize the operational cost of railway company. The model is transformed into a single-objective model, and then we design a harmony search algorithm to solve it. Finally, the model is validated by a numerical example. The results of this model as well as the scenarios of the single-objective models for minimizing operational costs and maximizing service accessibility are compared. From the perspective of service frequency and accessibility of each nodes, we know that the proposed method can balance conflicts between average speed between large nodes and service frequency of small and medium size nodes in high-speed railway network.

Simultaneous line planning and timetabling based on a combinational travel network for both trains and passengers: a mixed-integer linear programming approach

This paper is devoted to designing a mixed-integer linear programming to solve the simultaneous line planning and timetabling problem. A directed graph is first constructed to represent the combinational travel network for both candidate trains and passengers. Through this graph, it is easy to simultaneously describe trains’ operation choices, passengers’ travel choices, and their restrictive relations. Based on it, a mixed-integer linear programming model with many binary and non-negative integer decision variables is built to simultaneously optimize the line plan, timetable, and passenger travel choices, which can be efficiently solved using commercial solver CPLEX for small-scale network, while a decomposition strategy is required to combine with CPLEX for large-scale network. A set of numerical experiments are carried out to analyse the impacts of flow sub-units, number of candidate trains, and weight factors. Finally, we conduct two case studies for testing the practicability of our proposed method.

Energy model for motion planning of 2D-belt press line tending robots

Energy model for motion planning of 2D-belt press line tending robots

Using requirement-functional-logical-physical models to support early assembly process planning for complex aircraft systems integration

The assembly line process planning connects product design and manufacturing through translating design information to assembly integration sequence. The assembly integration sequence defines the aircraft system components installation and test precedence of an assembly process. This activity is part of the complex systems integration and verification process from a systems engineering view. In this paper, the complexity of modern aircraft is defined by classifying aircraft system interactions in terms of energy flow, information data, control signals and physical connections. At the early conceptual design phase of assembly line planning, the priority task is to understand these product complexities, and generate the installation and test sequence that satisfies the designed system function and meet design requirements. This research proposes a novel method for initial assembly process planning that accounts for both physical and functional integrations. The method defines aircraft system interactions by using systems engineering concepts based on traceable RFLP (Requirement, Functional, Logical and Physical) models and generate the assembly integration sequence through a structured approach. The proposed method is implemented in an industrial software environment, and tested in a case study. The result shows the feasibility and potential benefits of the proposed method.

An optimization model for line planning and timetabling in automated urban metro subway networks. A case study

In this paper we present a Mixed Integer Linear Programming model that we developed as part of a pilot study requested by the R&D company Metrolab® in order to design tools for finding solutions for line planning and timetable situations in automated urban metro subway networks. Our model incorporates important factors in public transportation systems from both, a cost-oriented and a passenger-oriented perspective, as time-dependent demands, interchange stations, short-turns and technical features of the trains in use. The incoming flows of passengers are modeled by means of piecewise linear demand functions which are parameterized in terms of arrival rates and bulk arrivals. Decisions about frequencies, train capacities, short-turning and timetables for a given planning horizon are jointly integrated to be optimized in our model. Finally, a novel matheuristic approach is proposed to solve the problem. The results of extensive computational experiments are reported to show its applicability and effectiveness to handle real-world subway networks.

Resolving instability in railway timetabling problems

A significant growth of the railway transportation demand is forecasted in the next decades which needs an increase of network capacity. Where possible, infrastructure upgrading can provide extra capacity; although in some cases, this is not enough to satisfy the entire transportation demand even if optimised timetabling is performed. We propose a heuristic model to develop a stable timetable which maximises the satisfaction of transportation demand in situations where network capacity is limited. In case the demand cannot be fully satisfied, the model relaxes the given line plan and timetable design parameters. The aim is to keep as many train services as possible and reduce the level of service minimally. We develop a mixed integer linear programming (MILP) model for minimising the cycle time to find an optimised stable timetable for the given line plan. The heuristic iteratively solves the MILP model and applies relaxation measures. We tested the model on the Dutch network. The results showed that the model can generate stable timetables by removing train services from the critical circuit, and also, higher transportation demand can be satisfied by additionally relaxing timetable design parameters.

A framework for integrating stakeholder preferences when deciding on power transmission line corridors

Decisions about urban space and especially regarding power transmission lines are of great public interest, because their visibility affects citizens for decades. With citizens’ increasing awareness, they expect to be transparently informed, their concerns to be taken seriously and that decision-makers base their decisions rationally on facts and laws. In this paper, we present a 3D Decision Support System (3D DSS) that tackles this issue and allows decision-makers to find an optimal transmission line corridor on such rational basis and by considering stakeholder’s preferences regarding multiple criteria. We examined its reliability regarding the ability of predicting transmission line corridors realistically—as stakeholders would expect them—by carrying out a study in central Switzerland with 10 grid planning experts and government representatives. Moreover, we investigated the extent to which graphic representations may support decision-makers firstly in evaluating a transmission line corridor modeled by the 3D DSS, secondly in considering and improving a human-defined scenario for transmission line planning, and thirdly in changing their opinion about a human-defined path. For this, a questionnaire was statistically evaluated by means of exploratory analysis, correlation analysis, and regression analysis. The results on the investigated visual analytics approach showed that it supports the evaluation of the corridor modeled by the 3D DSS as well as of the scenario defined by the stakeholders. As our new approach allows stakeholders to evaluate a transmission line path they consider to be optimal for land and population, it has a high potential for supporting rational group decision-making when considering different opinions.

Hybrid spider monkey optimisation algorithm for multi-level planning and scheduling problems of assembly lines

The production planning and scheduling problems of printed circuit board (PCB) assembly line robustly influence the production efficiency of PCB industries. The current study focuses on the optimisation of the multi-level planning and scheduling problem by minimising the cycle time of the PCB assembly lines. Two levels of planning problems i.e. component allocation problem (CAP) and component placement sequence problem (CPSP) are solved simultaneously using mixed integer linear programming model. In CAP, a model is formulated with the objective of balancing the workload among the surface mounted machines (SMM), while in CPSP, a model is formulated to find optimum sequencing for allocated components at each SMM. A novel hybrid spider monkey optimisation (HSMO) algorithm is proposed with the addition of new sorting food sources and genetic operators in the standard spider monkey optimisation (SMO) algorithm. The performance of the proposed HSMO algorithm is validated by comparing the solutions with well-known algorithms, i.e. genetic algorithm (GA), particle swarm optimisation (PSO), simulated annealing (SA) and artificial bee colony (ABC) algorithms. The proposed HSMO algorithm is tested on different problem set instances scaled based on the realistic production of PCB industries. The detailed analysis of results indicates that the proposed HSMO algorithm outperforms the compared algorithms in efficiency and effectiveness.

Maintenance timetable planning based on mesoscopic infrastructure and the transport service intention

Planners of maintenance intervals and operations have a strong need for rapid development and assessment of comprehensive and reliable timetable scenarios, which are able to satisfy the requirements of both, the train operating company and the infrastructure operating company. To address these requirements, in this paper we present a use case that is based on the ‘track-choice and line-rotation’ extension of ‘PESP’, the commonly known model for the generation of periodic event schedules. We call the extended model ‘TCFPESP’. This model takes into account the event flexibility requirement of the ‘service intention’ and makes use of a mesoscopic track infrastructure representation. Both properties support an iterative timetable development process with a ‘progressive feasibility assessment’, a feature that is requested in practice.The ‘service intention’ represents the functional timetable specification. The specification is given by an integrated line concept consisting of a set of lines with data defining their types, frequencies, stop sequence, rotation times and connections. Our proposed model takes functional and operational timetable specifications as input and is applied in an iterative way by changing technical parameters in order to generate a timetable with a feasible capacity allocation.Both, the service intention as well as the mesoscopic infrastructure representation can be configured in the line planning and timetabling system Viriato. This system is widely used by public transport planners and operators. It is therefore possible to configure our timetable model by a standard planning tool.After the description of the methods developed, we provide a practical proof of concept by testing the use case for different maintenance scenarios. Thereby we can show that, based on the service intention planners are able to quickly develop feasible timetable scenarios for maintenance intervals. The use case presented in this paper refers to generating short-term timetable scenarios but can also be used in long-term strategic planning.

Maintenance Location Routing for Rolling Stock Under Line and Fleet Planning Uncertainty

Rolling stock needs regular maintenance in a maintenance facility. Rolling stock from different fleets are routed to maintenance facilities by interchanging the destinations of trains at common stations and by using empty drives. We consider the problem of locating maintenance facilities in a railway network under uncertain or changing line planning, fleet planning, and other uncertain factors. These uncertainties and changes are modeled by a discrete set of scenarios. We show that this new problem is NP-hard and provide a two-stage stochastic programming and a two-stage robust optimization formulation. The second-stage decision is a maintenance routing problem with similarity to a minimum cost-flow problem. We prove that the facility location decisions remain unchanged under a simplified routing problem, and this gives rise to an efficient mixed-integer programming (MIP) formulation. This result also allows us to find an efficient decomposition algorithm for the robust formulation based on scenario addition (SA). Computational work shows that our improved MIP formulation can efficiently solve instances of industrial size. SA improves the computational time for the robust formulation even further and can handle larger instances due to more efficient memory usage. Finally, we apply our algorithms on practical instances of the Netherlands Railways and give managerial insights.

Robust Optimization for Microgrid Defense Resource Planning and Allocation Against Multi-Period Attacks

This paper investigates a microgrid defense resource planning and allocation problem with the consideration of multi-period attacks. The defensive transmission lines and distributed generators (DGs) are, respectively, planned and allocated to mitigate the multi-period attack damage on transmission lines and minimize the shed loads for microgrid, based on a multi-period defender–attacker–defender model. Robust optimization technique is utilized for the problem formulation, resulting in a two-stage decision process: in the first stage, the defender proposes defensive line plan and DG allocation scheme for the purpose of minimizing the attacker’s damage; and in the second stage, the attacker disrupts the transmission lines of microgrid system aiming at the maximum damage by the multi-period attacks, then the defender reacts to optimize the power flow on the remaining microgrid system to minimize the shed loads. Solution process is developed based on the customized column-and-constraint generation algorithm. The effectiveness and superiority of the proposed model and algorithm are validated with numerical experiments. In addition, sensitivity analysis is also carried out with various parameters and settings.

Research on Planning and Model Design of Micro-cycle Bus Line Based on Metro Station Connection

Public transport coverage fails to keep pace with urbanization and urban expansion, which makes the “last kilometer" problem of residents’ travel increasingly prominent”. However, the practice has proved that microcirculation public transportation plays an important role in expanding the coverage of public transportation and promoting the integration of public transportation. Therefore, this paper takes a city bus community as an example. Firstly, it analyses the bus travel demand of commuters connecting to the subway station during the early workday rush hours on basis of IC Big Data, obtains candidate stations of microcirculation bus lines through K-means clustering. Secondly, it establishes the model, the target of which is to minimize the cost residents' travel and bus operation, under the limited condition of walking distance, passenger number, station spacing and departure frequency. Finally, the genetic algorithm is used to find the optimal solution of the model, so it’s no doubt that the most feasible circular bus route is obtained. The results have positive significance for promoting the construction and operation of public transport integration and promoting the convenience and efficiency of public transport travel.

A Study on conceptual design of mini FSRU as LNG receiving facility

One of prioritizes of the government of Indonesia is to provide electricity in Papua regions to reduce electricity disparity in Indonesia. According to recent Power Supply Business Plan of PT Perusahaan Listrik Negara (Persero), there are more than 50 power plants are planned to build in Papua and Maluku regions. One of power plants which has considerable high capacity is located in Jayapura, Papua Province. This study addresses the conceptual design for three power plants in this area with capacities of 50 MW, 50 MW and 40 MW. The power plants are assumed to be supplied by natural gas from Floating Storage and Regasification Unit (FSRU). This concept was chosen because of the sloping contour of the seabed and to reduce the use of land for the receiving terminal. To supply the FSRU, a 30,000 m3 small scale LNG vessel is used for a shuttle vessel with estimated roundtrip is 15 days. The conceptual design consists of determination of cargo tank capacity, designing lines plan and general arrangement of FSRU, stability calculation, Process Flow Diagram (PFD), Process and Instrumentation Diagram (P&ID) for loading and regasification processes at the FSRU.

Passenger flow forecast for customized bus based on time series fuzzy clustering algorithm

Abstract Customized bus services are conducive to improving urban traffic and environment, and have attracted widespread attention. However, the problems encountered in the new customized bus mode include the large difference between the basis of customized bus passenger flow data analysis and the basis of the traditional bus passenger flow data analysis, and the difficulty in different vehicle scheduling caused by the combination of traditional and customized bus modes. We propose a customized bus passenger flow analysis algorithm and multi-destination customized bus line capacity scheduling algorithm, and display them in an intuitive way. The experimental results show that the algorithm model established in this paper can basically meet the data requirements of operation and management, and can provide decision support for customized bus line planning.