15 research outputs found

    Scattered tree death contributes to substantial forest loss in California

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    In recent years, large-scale tree mortality events linked to global change have occurred around the world. Current forest monitoring methods are crucial for identifying mortality hotspots, but systematic assessments of isolated or scattered dead trees over large areas are needed to reduce uncertainty on the actual extent of tree mortality. Here, we mapped individual dead trees in California using sub-meter resolution aerial photographs from 2020 and deep learning-based dead tree detection. We identified 91.4 million dead trees over 27.8 million hectares of vegetated areas (16.7-24.7% underestimation bias when compared to field data). Among these, a total of 19.5 million dead trees appeared isolated, and 60% of all dead trees occurred in small groups ( ≤ 3 dead trees within a 30 × 30 m grid), which is largely undetected by other state-level monitoring methods. The widespread mortality of individual trees impacts the carbon budget and sequestration capacity of California forests and can be considered a threat to forest health and a fuel source for future wildfires

    A Fast and Self-Repairing Genetic Programming Designer for Logic Circuits

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    Usually, important parameters in the design and implementation of combinational logic circuits are the number of gates, transistors, and the levels used in the design of the circuit. In this regard, various evolutionary paradigms with different competency have recently been introduced. However, while being advantageous, evolutionary paradigms also have some limitations including: a) lack of confidence in reaching at the correct answer, b) long convergence time, and c) restriction on the tests performed with higher number of input variables. In this paper, we have implemented a genetic programming approach that given a Boolean function, outputs its equivalent circuit such that the truth table is covered and the minimum number of gates (and to some extent transistors and levels) are used. Furthermore, our implementation improves the aforementioned limitations by: Incorporating a self-repairing feature (improving limitation a); Efficient use of the conceivable coding space of the problem, which virtually brings about a kind of parallelism and improves the convergence time (improving limitation b). Moreover, we have applied our method to solve Boolean functions with higher number of inputs (improving limitation c). These issues are verified through multiple tests and the results are reported

    Training multi-agent teams from zero knowledge with the competitive coevolutionary team-based particle swarm optimiser

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    A new competitive coevolutionary team-based particle swarm optimiser (CCPSO(t)) algorithm is developed to train multi-agent teams from zero knowledge. The CCPSO(t) algorithm is applied to train a team of agents to play simple soccer. The algorithm uses the charged particle swarm optimiser in a competitive and cooperative coevolutionary training environment to train neural network controllers for the players. The CCPSO(t) algorithm makes use of the FIFA league ranking relative fitness function to gather detailed performance metrics from each game played. The training performance and convergence behaviour of the particle swarm is analysed. A hypothesis is presented that explains the lack of convergence in the particle swarms. After applying a clustering algorithm on the particle positions, a detailed visual and quantitative analysis of the player strategies is presented. The final results show that the CCPSO(t) algorithm is capable of evolving complex gameplay strategies for a complex non-deterministic game.http://link.springer.com/journal/5002017-02-28hb201

    Massively parallel reasoning in transitive relationship hierarchies

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    This research focuses on building a parallel knowledge representation and reasoning system for the purpose of making progress in realizing human-like intelligence. To achieve human-like intelligence, it is necessary to model human reasoning processes by programs. Knowledge in the real world is huge in size, complex in structure, and is also constantly changing even in limited domains. Unfortunately, reasoning algorithms are very often intractable, which means that they are too slow for any practical applications. One technique to deal with this problem is to design special-purpose reasoners. Many past Al systems have worked rather nicely for limited problem sizes, but attempts to extend them to realistic subsets of world knowledge have led to difficulties. Even special purpose reasoners are not immune to this impasse. In this work, to overcome this problem, we are combining special purpose reasoners with massive We have developed and implemented a massively parallel transitive closure reasoner, called Hydra, that can dynamically assimilate any transitive, binary relation and efficiently answer queries using the transitive closure of all those relations. Within certain limitations, we achieve constant-time responses for transitive closure queries. Hydra can dynamically insert new concepts or new links into a. knowledge base for realistic problem sizes. To get near human-like reasoning capabilities requires the possibility of dynamic updates of the transitive relation hierarchies. Our incremental, massively parallel, update algorithms can achieve almost constant time updates of large knowledge bases. Hydra expands the boundaries of Knowledge Representation and Reasoning in a number of different directions: (1) Hydra improves the representational power of current systems. We have developed a set-based representation for class hierarchies that makes it easy to represent class hierarchies on arrays of processors. Furthermore, we have developed and implemented two methods for mapping this set-based representation onto the processor space of a Connection Machine. These two representations, the Grid Representation and the Double Strand Representation successively improve transitive closure reasoning in terms of speed and processor utilization. (2) Hydra allows fast rerieval and dynamic update of a large knowledge base. New fast update algorithms are formulated to dynamically insert new concepts or new relations into a knowledge base of thousands of nodes. (3) Hydra provides reasoning based on mixed hierarchical representations. We have designed representational tools and massively parallel reasoning algorithms to model reasoning in combined IS-A, Part-of, and Contained-in hierarchies. (4) Hydra\u27s reasoning facilities have been successfully applied to the Medical Entities Dictionary, a large medical vocabulary of Columbia Presbyterian Medical Center. As a result of (1) - (3), Hydra is more general than many current special-purpose reasoners, faster than currently existing general-purpose reasoners, and its knowledge base can be updated dynamically

    Методы и алгоритмы систем искусственного интеллекта

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    Учебное пособие включает основные сведения по методам и алгоритмам создания интеллектуальных систем. Приведенные примеры учебных задач дают представление о различных подходах к построению систем искусственного интеллекта. Предназначено для специалистов в области информатики и искусственного интеллекта, студентов и аспирантов вузов

    A genetic parallel programming based logic circuit synthesizer.

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    Lau, Wai Shing.Thesis submitted in: November 2006.Thesis (M.Phil.)--Chinese University of Hong Kong, 2007.Includes bibliographical references (leaves 85-94).Abstracts in English and Chinese.Abstract --- p.iAcknowledgement --- p.ivChapter 1 --- Introduction --- p.1Chapter 1.1 --- Field Programmable Gate Arrays --- p.2Chapter 1.2 --- FPGA technology mapping problem --- p.3Chapter 1.3 --- Motivations --- p.5Chapter 1.4 --- Contributions --- p.6Chapter 1.5 --- Thesis Organization --- p.9Chapter 2 --- Background Study --- p.11Chapter 2.1 --- Deterministic approach to technology mapping problem --- p.11Chapter 2.1.1 --- FlowMap --- p.12Chapter 2.1.2 --- DAOMap --- p.14Chapter 2.2 --- Stochastic approach --- p.15Chapter 2.2.1 --- Bio-Inspired Methods for Multi-Level Combinational Logic Circuit Design --- p.15Chapter 2.2.2 --- A Survey of Combinational Logic Circuit Representations in stochastic algorithms --- p.17Chapter 2.3 --- Genetic Parallel Programming --- p.20Chapter 2.3.1 --- Accelerating Phenomenon --- p.22Chapter 2.4 --- Chapter Summary --- p.23Chapter 3 --- A GPP based Logic Circuit Synthesizer --- p.24Chapter 3.1 --- Overall system architecture --- p.25Chapter 3.2 --- Multi-Logic-Unit Processor --- p.26Chapter 3.3 --- The Genotype of a MLP program --- p.28Chapter 3.4 --- The Phenotype of a MLP program --- p.31Chapter 3.5 --- The Evolution Engine --- p.33Chapter 3.5.1 --- The Dual-Phase Approach --- p.33Chapter 3.5.2 --- Genetic operators --- p.35Chapter 3.6 --- Chapter Summary --- p.38Chapter 4 --- MLP in hardware --- p.39Chapter 4.1 --- Motivation --- p.39Chapter 4.2 --- Hardware Design and Implementation --- p.40Chapter 4.3 --- Experimental Settings --- p.43Chapter 4.4 --- Experimental Results and Evaluations --- p.46Chapter 4.5 --- Chapter Summary --- p.50Chapter 5 --- Feasibility Study of Multi MLPs --- p.51Chapter 5.1 --- Motivation --- p.52Chapter 5.2 --- Overall Architecture --- p.53Chapter 5.3 --- Experimental settings --- p.55Chapter 5.4 --- Experimental results and evaluations --- p.59Chapter 5.5 --- Chapter Summary --- p.59Chapter 6 --- A Hybridized GPPLCS --- p.61Chapter 6.1 --- Motivation --- p.62Chapter 6.2 --- Overall system architecture --- p.62Chapter 6.3 --- Experimental settings --- p.64Chapter 6.4 --- Experimental results and evaluations --- p.66Chapter 6.5 --- Chapter Summary --- p.70Chapter 7 --- A Memetic GPPLCS --- p.71Chapter 7.1 --- Motivation --- p.72Chapter 7.2 --- Overall system architecture --- p.72Chapter 7.3 --- Experimental settings --- p.76Chapter 7.4 --- Experimental results and evaluations --- p.77Chapter 7.5 --- Chapter Summary --- p.80Chapter 8 --- Conclusion --- p.82Chapter 8.1 --- Future work --- p.83Bibliography --- p.8
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