Feature-rich distance-based terrain synthesis

This thesis describes a novel terrain synthesis method based on distances in a weighted graph. The method begins with a regular lattice with arbitrary edge weights; heights are determined by path cost from a set of generator nodes. The shapes of individual terrain features, such as mountains, hills, and craters, are specified by a monotonically decreasing profile describing the cross-sectional shape of a feature, while the locations of features in the terrain are specified by placing the generators. Pathing places ridges whose initial location have a dendritic shape. The method is robust and easy to control, making it possible to create pareidolia effects. It can produce a wide range of realistic synthetic terrains such as mountain ranges, craters, faults, cinder cones, and hills. The algorithm incorporates random graph edge weights, permits the inclusion of multiple topography profiles, and allows precise control over placement of terrain features and their heights. These properties all allow the artist to create highly heterogeneous terrains that compare quite favorably to existing methods

Evolving artificial terrains with automated genetic terrain programing

La industria del videojuego afronta en la actualidad un gran reto: mantener el coste del desarrollo de los proyectos bajo control a medida que estos crecen y se hacen más complejos. La creación de los contenidos de los juegos, que incluye el modelado de personajes, mapas y niveles, texturas, efectos sonoros, etc, representa una parte fundamental del costo final de producción. Por eso, la industria está cada vez más interesada en la utilización de métodos procedurales de generación automática de contenidos. Sin embargo, crear y afinar los métodos procedurales no es una tarea trivial. En esta memoria, se describe un método procedural basado en Programación Genética, que permite la generación automática de terrenos para videojuegos. Los terrenos presentan características estéticas, y no requieren ningún tipo de parametrización para definir su aspecto. Así, el ahorro de tiempo y la reducción de costes en el proceso de producción es notable. Para conseguir los objetivos, se utiliza Programación Genética de Terrenos. La primera implementación de GTP utilizó Evolución Interactiva, en que la presencia del usuario que guía el proceso evolutivo es imprescindible. A pesar de los buenos resultados, el método está limitado por la fatiga del usuario (común en los métodos interactivos). Para resolver esta cuestión se desarrolla un nuevo modelo de GTP en el que el proceso de búsqueda es completamente automático, y dirigido por una función de aptitudo. La función considera accesibilidad de los terrenos y perímetros de los obstáculos. Los resultados obtenidos se incluyeron como parte de un videojuego real.Nowadays video game industry is facing a big challenge: keep costs under control as games become bigger and more complex. Creation of game content, such as character models, maps, levels, textures, sound effects and so on, represent a big slice of total game production cost. Hence, video game industry is increasingly turning to procedural content generation to amplify the cost-effectiveness of video game designers' efforts. However, creating and fine tunning procedural methods for automated content generation is a time consuming task. In this thesis we detail a Genetic Programming based procedural content technique to generate procedural terrains. Those terrains present aesthetic appeal and do not require any parametrization to control its look. Thus, allowing to save time and help reducing production costs. To accomplish these features we devised the Genetic Terrain Programming (GTP) technique. The first implementation of GTP used an Interactive Evolutionary Computation (IEC) approach, were a user guides the evolutionary process. In spite of the good results achieved this way, this approach was limited by user fatigue (common in IEC systems). To address this issue a second version of GTP was developed where the search is automated, being guided by a direct fitness function. That function is composed by two morphological metrics: terrain accessibility and obstacle edge length. The combination of the two metrics allowed us remove the human factor form the evolutionary process and to find a wide range of aesthetic and fit terrains. Procedural terrains produced by GTP are already used in a real video game.Ministerio de Educación y Ciencia (TIN2007-68083-C02-01); (TIN2008-05941); (TIN2011-28627-C04) Junta de Extremadura (GRU-09105); (GR10029) Junta de Andalucía (TIC-6083

MSATT: Mars Surface and Atmosphere Through Time

The papers published here are based on a workshop entitled "Mars: Past, Present, and Future: Results from the MSATT Program." MSATT (Mars Surface and Atmosphere Through Time) was the last of the Mars data analysis programs and functioned mainly through a series of focused workshops, the final one being held at the Lunar and Planetary Institute in Houston, Texas on November 15-17, 1993. The program began and ended with workshops that brought the entire MSATT community together. Here you will find papers that address the geology, mineralogy, and meteorology of Mars in an effort to assess how the surface and atmosphere of this fascinating planet have evolved over time. Could early Mars have been warmed by a brighter young sun instead of a massive greenhouse effect? Were glaciers and hydrological cycles part of Mars' relatively recent past, or was aeolian activity responsible for the putative glacial features? Do the SNCs come from a single source region, or is more than one site involved? And what really are the properties of Martian soils and what do they tell us about the weathering environment? Clearly, these are difficult questions, but progress toward answers can be found in this issue. Also contained in this issue are a mix of theoretical and observational papers that deal with the general circulation of the current atmosphere, the factors that drive it (dust properties), and the role it plays in controlling the current climate system

Magnetic surveys locate Late Bronze Age corrals

A new type of livestock enclosure from the Late Bronze Age has been discovered. Stone walls outline a pair of circular or oval areas that may be up to 50 m in diameter. The stone walls are invisible at the surface; they were discovered in north-western Crimea and only with the aid of remote sensing and geophysical survey

Barnes Update Applied in the Gauss−Newton Method: An Improved Algorithm to Locate Bond Breaking Points

A mechanochemical reaction is a reaction induced by mechanical energy. A general accepted model for this type of reactions consists in a first order perturbation on the associated potential energy surface (PES) of the unperturbed molecular system due to mechanical stress or pulling force. Within this theoretical framework, the so-called optimal barrier breakdown points or optimal bond breaking points (BBPs) are critical points of the unperturbed PES where the Hessian matrix has a zero eigenvector that coincides with the gradient vector. Optimal BBPs are 'catastrophe points' that are par- ticularly important because its associated gradient indicates how to optimally harness tensile forces to induce reactions by transforming a chemical reaction into a barrierless process. Building on a previous method based on a nonlinear least squares minimiza- tion to locate BBPs (Bofill et al., J. Chem. Phys. 2017, 147, 152710-10), we propose a new algorithm to locate BBPs of any molecular system based on the Gauss-Newton method combined with the Barnes update for the nonsymmetric Jacobian matrix, which is shown to be more appropriate than the Broyden update. The efficiency of the new method is demonstrated for a multidimensional model PES and two medium size molec- ular systems of interest in enzymatic catalysis and mechanochemistry

Historic Conservation Landscapes on Fort Hood, Texas: The Civilian Conservation Corps and Cultural Landscape Change in Central Texas

The Civilian Conservation Corps (CCC) was probably the most popular of President Franklin D. Roosevelt's New Deal programs. Many studies have examined the contribution of the CCC in national and state parks and forests, but less attention has been directed towards soil conservation work performed by enrollees on farms and ranches across the country. This dissertation examines cultural landscapes created by the CCC on farms and ranches in Central Texas that are now part of the Fort Hood Military Reservation. Cultural landscapes created by the CCC in the 1930s are significant because they represent large-scale federal government intervention into farming practices and planning on private land. Dramatic transformations occurred in both the conservation movement and on the land itself. This can be investigated through archaeological sites associated with activities of the CCC on Fort Hood from its period of operation (i.e., from 1933 to 1942). The significance of identified archaeological sites is evaluated based on the Secretary of the Interior's guidelines for evaluating archaeological sites for inclusion in the National Register of Historic Places. Through the CCC, America's civilians transformed millions of acres of land across the United States from 1933 to 1942 in an effort to conserve natural resources that had been severely overexploited in preceding decades. Soil conservation and other New Deal agricultural programs primarily benefited land owners, but research on Fort Hood suggests that some tenants and sharecroppers benefited as well. Soil conservation work performed by the CCC on private land changed the way America's farming population operated their farms and included ordinary farmers in the conservation movement. Conservation was no longer the sole concern of academics, but through the efforts of federal, state, and local governments, became a major concern of ordinary farmers. This study also explores how rural planning efforts involved farmers in the decision-making process more than ever before. The reorganization of the rural landscape of Central Texas attests to the degree to which conservation measures were accepted by individual farmers

Subdividing the savanna: the ecology of change in northern Tanzania

East African savannas are persistent socio-ecological systems undergoing unprecedented change. This dissertation focuses on the emerging agro-pastoral system of Maasai herders in the savanna lands adjacent to Tanzania’s Tarangire National Park. As pastoralists adopt cultivation, the relationship between humans and the land is changed. The new dynamics threaten the resilience of savanna systems. I examine three aspects of the human ecology of Maasai subsistence: changes in territory and political ecology, changes to the local common property system resulting from territorial compression, and how Maasai are responding to the production constraints of cultivation. I employed ethnography, social surveys, soil surveys and livestock demography to take a political ecology approach to investigating human-environment relations. Maasai territory is being fragmented by forces from within and without Maasai society. Poverty is increasing, due to market integration, high cattle mortality and population growth. Despite this, the adoption of cultivation cannot be explained by poverty alone. Poverty interacts with land tenure insecurity and with environmental stochasticity to create conditions conducive to the adoption of cultivation. Subdivision fragments the pastures which support pastoralism, reducing mobility and flexibility critical to dryland ecosystems. A village zoning plan has led to the emergence of a new common property regime that appears sufficient for current grazing and cultivation needs yet the historical pattern of land allocation means some villagers have greater access to protected pastures and water than others. Rich soils from abandoned kraals are also unequally distributed across the landscape. Pastoralists must negotiate limited cultivation experience, wildlife raids and labor shortages to integrate pastoral and agricultural production. Several trends suggest negative repercussions for future resilience of the socioecological system. Unequal resource distribution among land allocations, the history of interactions between stakeholder groups, and land use patterns that inadvertently concentrate resources among a few households are decreasing the flexibility demanded by semi-arid systems. To reduce the negative effects of cultivation, efforts should focus on improving yields on small plots, supporting livestock husbandry and integrating local residents and wildlife interests to build a resilient future

Reports of planetary geology and geophysics program, 1988

This is a compilation of abstracts of reports from Principal Investigators of NASA's Planetary Geology and Geophysics Program, Office of Space Science and Applications. The purpose is to document in summary form research work conducted in this program during 1988. Each report reflects significant accomplishments within the area of the author's funded grant or contract