A review of wildland fire spread modelling, 1990-present 3: Mathematical analogues and simulation models

In recent years, advances in computational power and spatial data analysis (GIS, remote sensing, etc) have led to an increase in attempts to model the spread and behvaiour of wildland fires across the landscape. This series of review papers endeavours to critically and comprehensively review all types of surface fire spread models developed since 1990. This paper reviews models of a simulation or mathematical analogue nature. Most simulation models are implementations of existing empirical or quasi-empirical models and their primary function is to convert these generally one dimensional models to two dimensions and then propagate a fire perimeter across a modelled landscape. Mathematical analogue models are those that are based on some mathematical conceit (rather than a physical representation of fire spread) that coincidentally simulates the spread of fire. Other papers in the series review models of an physical or quasi-physical nature and empirical or quasi-empirical nature. Many models are extensions or refinements of models developed before 1990. Where this is the case, these models are also discussed but much less comprehensively.Comment: 20 pages + 9 pages references + 1 page figures. Submitted to the International Journal of Wildland Fir

Fenchel Decomposition for Stochastic Mixed-IntegerProgramming

This paper introduces a new cutting plane method for two-stage stochastic mixed-integer programming (SMIP) called Fenchel decomposition (FD). FD usesa class of valid inequalities termed, FD cuts, which are derived based on Fenchel cutting planes from integer programming. We derive FD cuts based on both the first and second stage variables, and devise an FD algorithm for SMIP with binary first stage and establish finite convergence for mixed-binary second stage. We also derive alternative FD cuts based on the second stage variables only and use an idea from disjunctive programming to lift the cuts to the higher dimension space including the first stage variables. We then devise an FD-L algorithm based on the lifted FD cuts. Finally, we report on preliminary computational results based on example instances from the literature. The results are promising and show the lifted FD cuts to have better performance than the regular FD cuts. Furthermore, both the FD and FD-L algorithms outperform a standard solver on large-scaleinstances

Wind energy facility reliability and maintenance

Abstract The global wind power industry involves operations in highly stochastic environments and thus faces challenges in enhancing reliability and reducing maintenance costs. Earlier studies related to wind energy facility reliability and maintenance focused more on qualitative aspects, discussing the unique influencing factors in wind power operations and their effects on system performance. With operational experience accumulated for more than a decade, the most recent focus has shifted to a more structured approach using analytical and/or simulation methods. In this chapter, we provide a comprehensive account of the existing research regarding wind energy facility reliability and maintenance. We group the relevant studies into three major categories. The first category addresses the degradation and failure pattern of wind turbines, aiming at optimizing the operations and maintenance. The second and third categories discuss the reliability issues in a broader sense, focusing on reliability assessment at the wind farm level and at the overall power system level, respectively

Disaster Management: Initiating Emergency Response for Forest Fires

When a forest fire occurs, to cope with this disaster a range of facilities are needed. Although these facilities may be efficient, their usages should be coordinated according to the requirements needed for a particular forest fire. Initiating firefighting activities on time, especially arrival of fire water tender and the ground team onto fire areas in critical response time is crucial for effective fighting against forest fires. Additionally, when multiple fires occur during a dry season, the response planning, and coordination become vital to fighting fires. Therefore, emergency response planning/coordination gains paramount importance while firefighting. This study focuses on one of the most important aspect of the wildfire response phase: initial emergency response in fixed regional forest directorates and airports. In this study, a heuristic methodology is proposed to solve this problem with real map data by using Network Analyst toolbox under ArcGIS program, which is used to determine optimum route that minimize arrival time to forest fires. To show the applicability of the proposed methodology, forest fire data that was collected in Turkey is used