lon
Visualizing Multimodality in Combinatorial Search Landscapes
Sánchez-Díaz, Xavier F. C., Mengshoel, Ole Jakob
This work walks through different visualization techniques for combinatorial search landscapes, focusing on multimodality. We discuss different techniques from the landscape analysis literature, and how they can be combined to provide a more comprehensive view of the search landscape. We also include examples and discuss relevant work to show how others have used these techniques in practice, based on the geometric and aesthetic elements of the Grammar of Graphics. We conclude that there is no free lunch in visualization, and provide recommendations for future work as there are several paths to continue the work in this field.
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Subfunction Structure Matters: A New Perspective on Local Optima Networks
Thomson, S. L., Przewozniczek, M. W.
Local optima networks (LONs) capture fitness landscape information. They are typically constructed in a black-box manner; information about the problem structure is not utilised. This also applies to the analysis of LONs: knowledge about the problem, such as interaction between variables, is not considered. We challenge this status-quo with an alternative approach: we consider how LON analysis can be improved by incorporating subfunction-based information - this can either be known a-priori or learned during search. To this end, LONs are constructed for several benchmark pseudo-boolean problems using three approaches: firstly, the standard algorithm; a second algorithm which uses deterministic grey-box crossover; and a third algorithm which selects perturbations based on learned information about variable interactions. Metrics related to subfunction changes in a LON are proposed and compared with metrics from previous literature which capture other aspects of a LON. Incorporating problem structure in LON construction and analysing it can bring enriched insight into optimisation dynamics. Such information may be crucial to understanding the difficulty of solving a given problem with state-of-the-art linkage learning optimisers. In light of the results, we suggest incorporation of problem structure as an alternative paradigm in landscape analysis for problems with known or suspected subfunction structure.
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A Comparison of Machine Learning Algorithms for Predicting Sea Surface Temperature in the Great Barrier Reef Region
Quayesam, Dennis, Akubire, Jacob, Darkwah, Oliveira
Predicting Sea Surface Temperature (SST) in the Great Barrier Reef (GBR) region is crucial for the effective management of its fragile ecosystems. This study provides a rigorous comparative analysis of several machine learning techniques to identify the most effective method for SST prediction in this area. We evaluate the performance of ridge regression, Least Absolute Shrinkage and Selection Operator (LASSO), Random Forest, and Extreme Gradient Boosting (XGBoost) algorithms. Our results reveal that while LASSO and ridge regression perform well, Random Forest and XGBoost significantly outperform them in terms of predictive accuracy, as evidenced by lower Mean Squared Error (MSE), Mean Absolute Error (MAE), and Root Mean Squared Prediction Error (RMSPE). Additionally, XGBoost demonstrated superior performance in minimizing Kullback- Leibler Divergence (KLD), indicating a closer alignment of predicted probability distributions with actual observations. These findings highlight the efficacy of using ensemble methods, particularly XGBoost, for predicting sea surface temperatures, making them valuable tools for climatological and environmental modeling.
- Research Report > New Finding (0.48)
- Research Report > Experimental Study (0.34)
- Information Technology > Artificial Intelligence > Machine Learning > Ensemble Learning (1.00)
- Information Technology > Artificial Intelligence > Machine Learning > Statistical Learning > Regression (0.98)
- Information Technology > Artificial Intelligence > Machine Learning > Performance Analysis > Accuracy (0.78)
RASPNet: A Benchmark Dataset for Radar Adaptive Signal Processing Applications
Venkatasubramanian, Shyam, Kang, Bosung, Pezeshki, Ali, Rangaswamy, Muralidhar, Tarokh, Vahid
This work presents a large-scale dataset for radar adaptive signal processing (RASP) applications, aimed at supporting the development of data-driven models within the radar community. The dataset, called RASPNet, consists of 100 realistic scenarios compiled over a variety of topographies and land types from across the contiguous United States, designed to reflect a diverse array of real-world environments. Within each scenario, RASPNet consists of 10,000 clutter realizations from an airborne radar setting, which can be utilized for radar algorithm development and evaluation. RASPNet intends to fill a prominent gap in the availability of a large-scale, realistic dataset that standardizes the evaluation of adaptive radar processing techniques. We describe its construction, organization, and several potential applications, which includes a transfer learning example to demonstrate how RASPNet can be leveraged for realistic adaptive radar processing scenarios.
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- North America > United States > Montana (0.28)
- North America > United States > Idaho (0.28)
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- Energy (0.67)
- Government > Military (0.46)
- Government > Regional Government > North America Government > United States Government (0.45)
Counterfactual Analysis of Neural Networks Used to Create Fertilizer Management Zones
Morales, Giorgio, Sheppard, John
In Precision Agriculture, the utilization of management zones (MZs) that take into account within-field variability facilitates effective fertilizer management. This approach enables the optimization of nitrogen (N) rates to maximize crop yield production and enhance agronomic use efficiency. However, existing works often neglect the consideration of responsivity to fertilizer as a factor influencing MZ determination. In response to this gap, we present a MZ clustering method based on fertilizer responsivity. We build upon the statement that the responsivity of a given site to the fertilizer rate is described by the shape of its corresponding N fertilizer-yield response (N-response) curve. Thus, we generate N-response curves for all sites within the field using a convolutional neural network (CNN). The shape of the approximated N-response curves is then characterized using functional principal component analysis. Subsequently, a counterfactual explanation (CFE) method is applied to discern the impact of various variables on MZ membership. The genetic algorithm-based CFE solves a multi-objective optimization problem and aims to identify the minimum combination of features needed to alter a site's cluster assignment. Results from two yield prediction datasets indicate that the features with the greatest influence on MZ membership are associated with terrain characteristics that either facilitate or impede fertilizer runoff, such as terrain slope or topographic aspect.
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- North America > United States > Texas > Coleman County (0.04)
- North America > United States > Montana > Gallatin County > Bozeman (0.04)
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- Materials > Chemicals > Agricultural Chemicals (1.00)
- Food & Agriculture > Agriculture (1.00)
- Information Technology > Artificial Intelligence > Machine Learning > Neural Networks (1.00)
- Information Technology > Artificial Intelligence > Representation & Reasoning > Optimization (0.86)
- Information Technology > Artificial Intelligence > Machine Learning > Statistical Learning > Clustering (0.66)
Understanding fitness landscapes in morpho-evolution via local optima networks
Thomson, Sarah L., Goff, Léni K. Le, Hart, Emma, Buchanan, Edgar
Morpho-evolution (ME) refers to the simultaneous optimisation of a robot's design and controller to maximise performance given a task and environment. Many genetic encodings have been proposed which are capable of representing design and control. Previous research has provided empirical comparisons between encodings in terms of their performance with respect to an objective function and the diversity of designs that are evaluated, however there has been no attempt to explain the observed findings. We address this by applying Local Optima Network (LON) analysis to investigate the structure of the fitness landscapes induced by three different encodings when evolving a robot for a locomotion task, shedding new light on the ease by which different fitness landscapes can be traversed by a search process. This is the first time LON analysis has been applied in the field of ME despite its popularity in combinatorial optimisation domains; the findings will facilitate design of new algorithms or operators that are customised to ME landscapes in the future.
- Oceania > Australia > Victoria > Melbourne (0.05)
- North America > United States > Massachusetts > Middlesex County > Cambridge (0.04)
- Europe > United Kingdom > Scotland > City of Edinburgh > Edinburgh (0.04)
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- Information Technology > Artificial Intelligence > Robots (1.00)
- Information Technology > Artificial Intelligence > Machine Learning > Evolutionary Systems (1.00)
- Information Technology > Artificial Intelligence > Representation & Reasoning > Optimization (0.75)
- Information Technology > Artificial Intelligence > Representation & Reasoning > Search (0.67)
Towards the Inferrence of Structural Similarity of Combinatorial Landscapes
One of the most common problem-solving heuristics is by analogy. For a given problem, a solver can be viewed as a strategic walk on its fitness landscape. Thus if a solver works for one problem instance, we expect it will also be effective for other instances whose fitness landscapes essentially share structural similarities with each other. However, due to the black-box nature of combinatorial optimization, it is far from trivial to infer such similarity in real-world scenarios. To bridge this gap, by using local optima network as a proxy of fitness landscapes, this paper proposed to leverage graph data mining techniques to conduct qualitative and quantitative analyses to explore the latent topological structural information embedded in those landscapes. By conducting large-scale empirical experiments on three classic combinatorial optimization problems, we gain concrete evidence to support the existence of structural similarity between landscapes of the same classes within neighboring dimensions. We also interrogated the relationship between landscapes of different problem classes.
Extraction of Road Users' Behavior From Realistic Data According to Assumptions in Safety-Related Models for Automated Driving Systems
Certad, Novel, Tschernuth, Sebastian, Olaverri-Monreal, Cristina
In this work, we utilized the methodology outlined in the IEEE Standard 2846-2022 for "Assumptions in Safety-Related Models for Automated Driving Systems" to extract information on the behavior of other road users in driving scenarios. This method includes defining high-level scenarios, determining kinematic characteristics, evaluating safety relevance, and making assumptions on reasonably predictable behaviors. The assumptions were expressed as kinematic bounds. The numerical values for these bounds were extracted using Python scripts to process realistic data from the UniD dataset. The resulting information enables Automated Driving Systems designers to specify the parameters and limits of a road user's state in a specific scenario. This information can be utilized to establish starting conditions for testing a vehicle that is equipped with an Automated Driving System in simulations or on actual roads.
- Transportation > Ground > Road (1.00)
- Automobiles & Trucks (1.00)
Experimental Validation of Safe MPC for Autonomous Driving in Uncertain Environments
Batkovic, Ivo, Gupta, Ankit, Zanon, Mario, Falcone, Paolo
The full deployment of autonomous driving systems on a worldwide scale requires that the self-driving vehicle be operated in a provably safe manner, i.e., the vehicle must be able to avoid collisions in any possible traffic situation. In this paper, we propose a framework based on Model Predictive Control (MPC) that endows the self-driving vehicle with the necessary safety guarantees. In particular, our framework ensures constraint satisfaction at all times, while tracking the reference trajectory as close as obstacles allow, resulting in a safe and comfortable driving behavior. To discuss the performance and real-time capability of our framework, we provide first an illustrative simulation example, and then we demonstrate the effectiveness of our framework in experiments with a real test vehicle.
- Transportation > Ground > Road (1.00)
- Energy > Oil & Gas (1.00)
- Automobiles & Trucks (1.00)
Top 5 stocks to end the year, according to Artificial Intelligence
Danelfin has released its new December ranking of the stocks most likely to beat the market. Until now, the monthly rankings were based solely on the AI Score, a score that reflects each company's probability of beating the market (the S&P 500 TR for U.S. stocks and the STOXX 600 for European stocks) in the next 30 to 90 days. But it is important to also consider the risk associated with each stock. Therefore, Danelfin has created a new ranking, which ranks companies according to the AI Risk/Reward Score, which is an average of the AI Score and the Low Risk Score. The Low Risk Score is a score based on negative price fluctuations (semi-deviation) over the last 500 market days. The higher the score (from 1 to 10), the lower the downside risk.
- Consumer Products & Services (0.85)
- Banking & Finance > Trading (0.76)