scholarly journals Time-Dependent Alternative Route Planning: Theory and Practice

Algorithms ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 220
Author(s):  
Spyros Kontogiannis ◽  
Andreas Paraskevopoulos ◽  
Christos Zaroliagis
Keyword(s):  
Travel Time ◽  
Real World ◽  
Route Planning ◽  
Theory And Practice ◽  
Time Dependent ◽  
Planning Theory ◽  
Alternative Route ◽  
Alternative Graph ◽  
Query Algorithm ◽  
Alternative Routes

We consider the problem of computing a set of meaningful alternative origin-to-destination routes, in real-world road network instances whose arcs are accompanied by travel-time functions rather than fixed costs. In this time-dependent alternative route scenario, we present a novel query algorithm, called Time-Dependent Alternative Graph (TDAG), that exploits the outcome of a time-consuming preprocessing phase to create a manageable amount of travel-time metadata, in order to provide answers for arbitrary alternative-routes queries, in only a few milliseconds for continental-size instances. The resulting set of alternative routes is aggregated in the form of a time-dependent alternative graph, which is characterized by the minimum route overlap, small stretch factor, small size, and low complexity. To our knowledge, this is the first work that deals with the time-dependent setting in the framework of alternative routes. The preprocessed metadata prescribe the minimum travel-time informations between a small set of “landmark” nodes and all other nodes in the graph. The TDAG query algorithm carries out the work in two distinct phases: initially, a collection phase constructs candidate alternative routes; consequently, a pruning phase cautiously discards uninteresting or low-quality routes from the candidate set. Our experimental evaluation on real-world, time-dependent road networks demonstrates that TDAG performed much better (by one or two orders of magnitude) than the existing baseline approaches.

Cost-Optimal Time-dEpendent Routing with Time and Speed Constraints in Directed Acyclic Road Networks

2016 ◽  
Vol 15 (06) ◽  
pp. 1413-1450
Author(s):  
Yaqiong Liu ◽  
Hock Soon Seah ◽  
Guochu Shou
Keyword(s):  
Travel Time ◽  
Nonlinear Optimization ◽  
Fuel Consumption ◽  
Real World ◽  
Computer Games ◽  
Road Networks ◽  
Minimum Cost ◽  
Time Dependent ◽  
Optimal Time ◽  
Step Algorithm

Travel costs on road networks always change over time which implies road networks are time dependent. Most studies on time-dependent road networks simply find the shortest path with the least travel time without considering waiting at some nodes, or fuel consumption and toll fee. In real-world applications or computer games, waiting may be allowed at some nodes but disallowed at other nodes; a user can traverse an edge at different speeds; monetary travel cost contains fuel cost and toll fees; and users usually prefer the minimum-cost route under time and speed constraints. Therefore, we study Cost-Optimal Time-dEpendent Routing (COTER) problem with time and speed constraints. We utilize two fuel consumption models and compute the minimum fuel consumption with given travel time for highway edges via nonlinear optimization. We allow the toll fee function to be an arbitrary single-valued time-dependent function. We define an Optimal Cost (OC) function for each candidate node [Formula: see text], and derive the recurrence relation formula between [Formula: see text]’s incoming neighbors’ OC-functions and [Formula: see text]’s OC-functions. To solve COTER, we propose a five-step algorithm, namely, ALG-COTER, which uses Fibonacci-heap optimized Dijkstra, topological sorting, dynamic programming, binary min-heap optimization, nonlinear optimization, and backtracking algorithms. Experimental results on three real-world road networks of different sizes demonstrate that our algorithm finds the optimal route efficiently and is scalable to different parameters.

scholarly journals Dynamic on-line multimodal route planning with least expected travel time in the stochastic and time-dependent bus network

2019 ◽  
Vol 259 ◽  
pp. 01002
Author(s):  
Jinjian Li ◽  
Arnaud Doniec ◽  
Jacques Boonaert ◽  
Guillaume Lozenguez
Keyword(s):  
Path Planning ◽  
Travel Time ◽  
Optimal Path ◽  
Route Planning ◽  
Time Dependent ◽  
Planning System ◽  
Dynamic Path Planning ◽  
On Line ◽  
Dynamic Path ◽  
Bus Network

Route planning system in bus network is very important on providing passengers a better experience for public transportation services. This work presents a new on-line dynamic path planning algorithm in a stochastic and time-dependent bus network, with the objective of least expected travel time. Firstly, an initial optimal path is found when a passenger leaves from the starting location at time t for the destination location. Secondly, when the passenger reaches a bus stop, the real time traffic condition is checked to decide whether the optimal path should be modified and re-calculated. If so, the shortest path algorithm is re-applied to find the new path. The simulation scenario is executed to show the performance and efficiency of the proposed dynamic path planning system.

A Materialist Basis for Planning Theory and Practice: Comments on the Papers by Roweis and by Forester

1983 ◽  
Vol 1 (4) ◽  
pp. 469-479 ◽  
Author(s):  
C Jensen-Butler
Keyword(s):  
Social Practice ◽  
Scientific Explanation ◽  
Qualitative Change ◽  
Theory And Practice ◽  
Planning Theory ◽  
Rational Approach ◽  
Negative Consequences ◽  
Planning Practice ◽  
Base Analysis ◽  
Epistemological Position

Analysis of the practice of planning is increasingly being used to develop planning theory, The papers by Roweis and Forester in the second issue of Environment and Planning D: Society and Space base analysis of planning practice on hermeneutic, linguistic, and phenomenological approaches, as an alternative to the technical -rational approach to planning theory, In the present paper, I argue that the approaches adopted by these two authors create more problems than they solve, and a critique of Roweis's and Forester's theoretical ideas is made, It is argued that these approaches rest upon idealist ontological assumptions, rendering explanation of qualitative change (development) impossible. Discussion of Giddens's concept of structuration and of the negative consequences for scientific explanation of Habermas's epistemological position is presented, as both approaches are used by Roweis and Forester. Criticism is also made of the separation of territorial relations from relations of substance. Finally, the serious consequences of their approaches for scientific and social practice are outlined. I conclude that this type of approach cannot provide a satisfactory basis for planning theory, and furthermore, that the approach is inherently conservative. Some ideas arc presented concerning planning theory based on materialist ontological foundations.

Strategic collection planning: Theory and practice

Zoo Biology ◽  
1995 ◽  
Vol 14 (1) ◽  
pp. 5-25 ◽  
Author(s):  
Michael Hutchins ◽  
Kevin Willis ◽  
Robert J. Wiese
Keyword(s):  
Theory And Practice ◽  
Planning Theory

From Problem-Solving Paradigm to Co-Ontogenic Drift: How Do Learning Narratives Self-Generate?

Leonardo ◽  
2011 ◽  
Vol 44 (2) ◽  
pp. 133-138
Author(s):  
Johann van der Merwe ◽  
Julia Brewis
Keyword(s):  
Problem Solving ◽  
Real World ◽  
Design Education ◽  
Design Theory ◽  
Social Situation ◽  
Theory And Practice ◽  
Use Of Self ◽  
Real World Problems

It is now an accepted maxim in design theory and practice that real-world problems needing the attention of design practitioners are not neat and well-structured, but ill-structured and “wicked”—part of a larger, complex social situation. For design education, then, to take its lead from contemporary social, political and economic structures, it will have to seriously re-think its problem-solving paradigms. The authors investigate the use of self-generating learning narratives in the classroom and contrast the approach they introduce with the still-too-prevalent notion that knowledge can be transferred from teacher to student. Their methodology draws from ideas formulated by Maturana and Varela on autopoiesis, specifically the notion of co-ontogenic drift.

Performance Approximation for Time-Dependent Queues with Generally Distributed Abandonments

2021 ◽  
Author(s):  
Gregor Selinka ◽  
Raik Stolletz ◽  
Thomas I. Maindl
Keyword(s):  
Performance Measures ◽  
Real World ◽  
Queueing System ◽  
Time Dependent ◽  
Interval Length ◽  
Arrival Process ◽  
Real World Data ◽  
World Data ◽  
Extant Literature ◽  
Approximation Quality

Many stochastic systems face a time-dependent demand. Especially in stochastic service systems, for example, in call centers, customers may leave the queue if their waiting time exceeds their personal patience. As discussed in the extant literature, it can be useful to use general distributions to model such customer patience. This paper analyzes the time-dependent performance of a multiserver queue with a nonhomogeneous Poisson arrival process with a time-dependent arrival rate, exponentially distributed processing times, and generally distributed time to abandon. Fast and accurate performance approximations are essential for decision support in such queueing systems, but the extant literature lacks appropriate methods for the setting we consider. To approximate time-dependent performance measures for small- and medium-sized systems, we develop a new stationary backlog-carryover (SBC) approach that allows for the analysis of underloaded and overloaded systems. Abandonments are considered in two steps of the algorithm: (i) in the approximation of the utilization as a reduced arrival stream and (ii) in the approximation of waiting-based performance measures with a stationary model for general abandonments. To improve the approximation quality, we discuss an adjustment to the interval lengths. We present a limit result that indicates convergence of the method for stationary parameters. The numerical study compares the approximation quality of different adjustments to the interval length. The new SBC approach is effective for instances with small numbers of time-dependent servers and gamma-distributed abandonment times with different coefficients of variation and for an empirical distribution of the abandonment times from real-world data obtained from a call center. A discrete-event simulation benchmark confirms that the SBC algorithm approximates the performance of the queueing system with abandonments very well for different parameter configurations. Summary of Contribution: The paper presents a fast and accurate numerical method to approximate the performance measures of a time‐dependent queueing system with generally distributed abandonments. The presented stationary backlog carryover approach with abandonment combines algorithmic ideas with stationary queueing models for generally distributed abandonment times. The reliability of the method is analyzed for transient systems and numerically studied with real‐world data.

scholarly journals Constitutional and post-constitutional problems: Reconsidering the issues of public interest, agonistic pluralism and private property in planning

2018 ◽  
Vol 18 (1) ◽  
pp. 5-23 ◽  
Author(s):  
Stefano Moroni
Keyword(s):  
Public Interest ◽  
Private Property ◽  
Theory And Practice ◽  
Planning Theory ◽  
Private Ownership ◽  
Research Perspective ◽  
Multi Level ◽  
Ownership Of Land ◽  
Planning Problems ◽  
Agonistic Pluralism

In the field of planning theory the discussion often seems to assume that all problems – for example, ethical or political ones – pertain to a single level or dimension. In fact, different and clearly separate “levels”, which raise problems of different kinds, can be distinguished. A “multi-level” approach therefore seems necessary. The underlying idea is that it is essential to distinguish more sharply between two analytical levels: the constitutional and post-constitutional levels. These levels are here understood mainly as analytical levels; that is, as standpoints that anyone can – at any time and even only hypothetically – assume to posit certain problems at the appropriate level and treat them by acknowledging the argumentative requirements suited to that level. This article uses such a multi-level approach to address three fundamental and currently much debated problems of planning theory and practice: the issue of “agonistic pluralism”; the issue of “public interest”; the question of “private ownership (of land)”. The contribution of this article falls within the neoinstitutionalist approaches to planning. The belief is that these approaches are shedding new light on planning problems and that research in this direction should be expanded. In this regard, this article attempts to make a contribution to this research perspective especially in analytical and methodological terms.

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