Procedural Generation and Rendering of Realistic, Navigable Forest Environments: An Open-Source Tool

Simulation of forest environments has applications from entertainment and art creation to commercial and scientific modelling. Due to the unique features and lighting in forests, a forest-specific simulator is desirable, however many current forest simulators are proprietary or highly tailored to a particular application. Here we review several areas of procedural generation and rendering specific to forest generation, and utilise this to create a generalised, open-source tool for generating and rendering interactive, realistic forest scenes. The system uses specialised L-systems to generate trees which are distributed using an ecosystem simulation algorithm. The resulting scene is rendered using a deferred rendering pipeline, a Blinn-Phong lighting model with real-time leaf transparency and post-processing lighting effects. The result is a system that achieves a balance between high natural realism and visual appeal, suitable for tasks including training computer vision algorithms for autonomous robots and visual media generation.Comment: 14 pages, 11 figures. Submitted to Computer Graphics Forum (CGF). The application and supporting configuration files can be found at https://github.com/callumnewlands/ForestGenerato

Optimal forest rotation age under efficient climate change mitigation

This paper considers the optimal rotation of forests when the carbon flows of forest growth and harvest are priced with an increasing price. Such an evolution of carbon price is generally associated with economically efficient climate change mitigation, and would provide incentives for the land-owner for enhanced carbon sequestration. With an infinitely long sequence of even-aged forest rotations, the optimal harvest age changes with subsequent rotations due to the changing carbon price. The first-order optimality conditions therefore also involve an infinite chain of lengths for consecutive forest rotations, and allow the approximation of the infinite-time problem with a truncated series of forest rotations. Illustrative numerical calculations show that when starting from bare land, the initial carbon price and its growth rate both primarily increase the length of the first rotation. With some combinations of the carbon pricing parameters, the optimal harvest age can be several hundred years if the forest carbon is released to the atmosphere upon harvest. This effect is not, however, entirely monotonous. Consequently, the currently optimal harvest ages are generally lower with higher rates of carbon price increase. This creates an interesting temporal aspect, suggesting that the supply of wood and carbon sequestration by forests can change considerably during subsequent rotations under an increasing price on carbon.Comment: in Forest Policy and Economics, 201

Pathways to gender equality? Implications of the interface between UNIFEM and the MDGs

The United Nation\u27s Millennium Development Goals were implemented in the year 2000 in efforts to re-energize social development initiatives on a global scale. As a UN organization, UNIFEM has an obligation to integrate this new framework for development into their current mandate, regardless of whether or not it is perceived as useful to UNIFEM\u27s goals and activities. This study explores the nature of the relationship between UNIFEM and the MDGs, and questions the implications this interface has on the construction of pathways to achieving gender equality and women\u27s empowerment. My findings suggest that over time, UNIFEM operates more like the bureaucratic organization of the UN, and less like a social movement organization many feminists expect it to be. This indicates a narrowing of the possibilities imaginable for the futures of women on the part of UNIFEM

The High-zz Universe Confronts Warm Dark Matter: Galaxy Counts, Reionization and the Nature of Dark Matter

We use $N$-body simulations to show that high-redshift galaxy counts provide an interesting constraint on the nature of dark matter, specifically Warm Dark Matter (WDM), owing to the lack of early structure formation these models. Our simulations include three WDM models with thermal-production masses of 0.8 keV, 1.3 keV, and 2.6 keV, as well as CDM. Assuming a relationship between dark halo mass and galaxy luminosity that is set by the observed luminosity function at bright magnitudes, we find that 0.8 keV WDM is disfavored by direct galaxy counts in the Hubble Ultra Deep Field at $>\!\!10\sigma$. Similarly, 1.3 keV WDM is statistically inconsistent at $2.2\sigma$. Future observations with JWST (and possibly HST via the Frontier Fields) could rule out $1.3$ keV WDM at high significance, and may be sensitive to WDM masses greater than 2.6 keV. We also examine the ability of galaxies in these WDM models to reionize the universe, and find that 0.8 keV and 1.3 keV WDM produce optical depths to the Cosmic Microwave Background (CMB) that are inconsistent at 68% C.L. with current Planck results, even with extremely high ionizing radiation escape fractions, and 2.6 keV WDM requires an optimistic escape fraction to yield an optical depth consistent with Planck data. Although CMB optical depth calculations are model dependent, we find a strong challenge for stellar processes alone to reionize the universe in a 0.8 keV and 1.3 keV WDM cosmology

Supporting multi-resolution out-of-core rendering of massive LiDAR point clouds through non-redundant data structures

This is an Accepted Manuscript of an article published by Taylor & Francis in INTERNATIONAL JOURNAL OF GEOGRAPHICAL INFORMATION SCIENCE on 28 Nov 2018, available at: https://doi.org/10.1080/13658816.2018.1549734[Abstract]: In recent years, the evolution and improvement of LiDAR (Light Detection and Ranging) hardware has increased the quality and quantity of the gathered data, making the storage, processing and management thereof particularly challenging. In this work we present a novel, multi-resolution, out-of-core technique, used for web-based visualization and implemented through a non-redundant, data point organization method, which we call Hierarchically Layered Tiles (HLT), and a tree-like structure called Tile Grid Partitioning Tree (TGPT). The design of these elements is mainly focused on attaining very low levels of memory consumption, disk storage usage and network traffic on both, client and server-side, while delivering high-performance interactive visualization of massive LiDAR point clouds (up to 28 billion points) on multiplatform environments (mobile devices or desktop computers). HLT and TGPT were incorporated and tested in ViLMA (Visualization for LiDAR data using a Multi-resolution Approach), our own web-based visualization software specially designed to work with massive LiDAR point clouds.This research was supported by Xunta de Galicia under the Consolidation Programme of Competitive Reference Groups, co-founded by ERDF funds from the EU [Ref. ED431C 2017/04]; Consolidation Programme of Competitive Research Units, co-founded by ERDF funds from the EU [Ref. R2016/037]; Xunta de Galicia (Centro Singular de Investigación de Galicia accreditation 2016/2019) and the European Union (European Regional Development Fund, ERDF) under Grant [Ref. ED431G/01]; and the Ministry of Economy and Competitiveness of Spain and ERDF funds from the EU [TIN2016-75845-P].Xunta de Galicia; ED431C 2017/04Xunta de Galicia; R2016/037Xunta de Galicia; ED431G/0

Coordinated Schematization for Visualizing Mobility Patterns on Networks

GPS trajectories of vehicles moving on a road network are a valuable source of traffic information. However, the sheer volume of available data makes it challenging to identify and visualize salient patterns. Meaningful visual summaries of trajectory collections require that both the trajectories and the underlying network are aggregated and simplified in a coherent manner. In this paper we propose a coordinated fully-automated pipeline for computing a schematic overview of mobility patterns from a collection of trajectories on a street network. Our pipeline utilizes well-known building blocks from GIS, automated cartography, and trajectory analysis: map matching, road selection, schematization, movement patterns, and metro-map style rendering. We showcase the results of our pipeline on two real-world trajectory collections around The Hague and Beijing

Live load distribution factors for glued-laminated timber bridges

Over the past years the United States Department of Agriculture - Forest Products Laboratory and the Federal Highway Administration have supported several research programs. This thesis is a result of a study sponsored by the Forest Products Laboratory, with the objective of determining how truckloads are distributed to the structural members of glued-laminated timber bridges. Glued-laminated timber girder bridges with glued-laminated timber deck panels and longitudinal glued-laminated timber deck bridges were the focus of this paper. Currently, the American Association of State Highway and Transportation Officials LRFD Bridge Design Specification provides live load distribution provisions for glued-laminated timber bridges. This paper investigates the existing live load distribution provisions for glued-laminated timber bridges utilizing field test data collected by Iowa State University researchers, laboratory test data, and analytical finite element modeling. From this data, simplified live load distribution equations were developed following methods established for other bridge types where needed to improve the accuracy of determining how truckloads are distributed to structural members of glued-laminated timber bridges

GSI3D model metadata report for HS2 area 3 (Newton Purcell to Thorpe Mandeville)

This report describes the 3D geological model of HS2 (High Speed 2 rail link) Area 3 (Newton Purcell to Thorpe Mandeville), created by A J Mark Barron with support from Steve Thorpe. The model was created as part of a set of nine fitted GSI3D models that cover the proposed HS2 rail route from the end of the HS2 London model to Birmingham and the West Coast Main Line near Lichfield. They were funded from the NERC/BGS Science Budget to promote BGS modelling and geological interpretation services to this important infrastructure project and to test methodologies and procedures for fitted bedrock models by multiple compilers. The report describes the model construction and purpose, with spatial limits and scale, sources of information, data processing, workflow, decisions, assumptions, rules and limitations, together with images of the model