631 research outputs found

    Intention-Aware Planner for Robust and Safe Aerial Tracking

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    The intention of the target can help us to estimate its future motion state more accurately. This paper proposes an intention-aware planner to enhance safety and robustness in aerial tracking applications. Firstly, we utilize the Mediapipe framework to estimate target's pose. A risk assessment function and a state observation function are designed to predict the target intention. Afterwards, an intention-driven hybrid A* method is proposed for target motion prediction, ensuring that the target's future positions align with its intention. Finally, an intention-aware optimization approach, in conjunction with particular penalty formulations, is designed to generate a spatial-temporal optimal trajectory. Benchmark comparisons validate the superior performance of our proposed methodology across diverse scenarios. This is attributed to the integration of the target intention into the planner through coupled formulations.Comment: 7 pages, 10 figures, submitted to 2024 IEEE International Conference on Robotics and Automation (ICRA

    (3R,6R,12R,20S,24R)-20,24-Ep­oxy­dammarane-3,6,12,25-tetra­ol

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    In the title compound, C30H52O5, the three six-membered rings are in chair conformations, the five-membered ring is in an envelope form and the tetra­hydro­furan ring has a conformation inter­mediate between half-chair and sofa. Intra­molecular O—H⋯O hydrogen bonds may influence the conformation of the mol­ecule. In the crystal, mol­ecules are linked by inter­molecular O—H⋯O hydrogen bonds, forming a three-dimensional network

    Efficient market hypothesis and fraud on the market theory: A new perspective for class actions

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    Following recent judgement of the Supreme Court of US (June 2014), several commentators had declared that “Securities class actions are here to stay” (insidecounsel.com – September 2014, 11). This paper provides a critical perspective on this judgement, which “implicates substantive issues at the intersection of economic theory, financial markets, and securities regulation” (128 Harv. L. Rev. 291 2014-2015, 291), and shows that we must be much more careful. This recent judgement is based on the Fraud on the Market Doctrine, which was introduced in 1973 in order to preserve the class action procedure in securities fraud litigation. The characteristic of the Fraud on the Market Doctrine is to have been structured from one of the most popular financial theory: Efficient Market Hypothesis. In this paper, by analysing the implementation of the Efficient Market Hypothesis in Fraud on the Market Theory, we argue that if the Supreme Court had to take position for a second time about the Fraud on the Market Doctrine it is due to the practical difficulties inherited from Efficient Market Hypothesis and that have raised several problems to the US courts, including the Supreme Court. This issue is illustrated by the definition of Efficient Market Hypothesis lawyers used (“most” vs “all”/”fully”). As this paper shows, if “Securities class actions are here to stay”, the opportunity to open such a class action is strongly reduced in the facts

    Are AlphaZero-like Agents Robust to Adversarial Perturbations?

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    The success of AlphaZero (AZ) has demonstrated that neural-network-based Go AIs can surpass human performance by a large margin. Given that the state space of Go is extremely large and a human player can play the game from any legal state, we ask whether adversarial states exist for Go AIs that may lead them to play surprisingly wrong actions. In this paper, we first extend the concept of adversarial examples to the game of Go: we generate perturbed states that are ``semantically'' equivalent to the original state by adding meaningless moves to the game, and an adversarial state is a perturbed state leading to an undoubtedly inferior action that is obvious even for Go beginners. However, searching the adversarial state is challenging due to the large, discrete, and non-differentiable search space. To tackle this challenge, we develop the first adversarial attack on Go AIs that can efficiently search for adversarial states by strategically reducing the search space. This method can also be extended to other board games such as NoGo. Experimentally, we show that the actions taken by both Policy-Value neural network (PV-NN) and Monte Carlo tree search (MCTS) can be misled by adding one or two meaningless stones; for example, on 58\% of the AlphaGo Zero self-play games, our method can make the widely used KataGo agent with 50 simulations of MCTS plays a losing action by adding two meaningless stones. We additionally evaluated the adversarial examples found by our algorithm with amateur human Go players and 90\% of examples indeed lead the Go agent to play an obviously inferior action. Our code is available at \url{https://PaperCode.cc/GoAttack}.Comment: Accepted by Neurips 202

    ‘Walking-stick ureters’ in ketamine abuse

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    Analysis of Affinely Equivalent Boolean Functions

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    By walsh transform, autocorrelation function, decomposition, derivation and modification of truth table, some new invariants are obtained. Based on invariant theory, we get two results: first a general algorithm which can be used to judge if two boolean functions are affinely equivalent and to obtain the affine equivalence relationship if they are equivalent. For example, all 8-variable homogenous bent functions of degree 3 are classified into 2 classes; second, the classification of the Reed-Muller code R(4,6)/R(1,6),R(3,7)/R(1,7),R(4,6)/R(1,6),R(3,7)/R(1,7), which can be used to almost enumeration of 8-variable bent functions

    Extracting the Quantum Geometric Tensor of an Optical Raman Lattice by Bloch State Tomography

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    In Hilbert space, the geometry of the quantum state is identified by the quantum geometric tensor (QGT), whose imaginary part is the Berry curvature and real part is the quantum metric tensor. Here, we propose and experimentally implement a complete Bloch state tomography to directly measure eigenfunction of an optical Raman lattice for ultracold atoms. Through the measured eigenfunction, the distribution of the complete QGT in the Brillouin zone is reconstructed, with which the topological invariants are extracted by the Berry curvature and the distances of quantum states in momentum space are measured by the quantum metric tensor. Further, we experimentally test a predicted inequality between the Berry curvature and quantum metric tensor, which reveals a deep connection between topology and geometry

    Snowfall Rate Retrieval Using Passive Microwave Measurements and Its Applications in Weather Forecast and Hydrology

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    (AMSU), Microwave Humidity Sounder (MHS) and Advance Technology Microwave Sounder (ATMS). ATMS is the followon sensor to AMSU and MHS. Currently, an AMSU and MHS based land snowfall rate (SFR) product is running operationally at NOAA/NESDIS. Based on the AMSU/MHS SFR, an ATMS SFR algorithm has also been developed. The algorithm performs retrieval in three steps: snowfall detection, retrieval of cloud properties, and estimation of snow particle terminal velocity and snowfall rate. The snowfall detection component utilizes principal component analysis and a logistic regression model. It employs a combination of temperature and water vapor sounding channels to detect the scattering signal from falling snow and derives the probability of snowfall. Cloud properties are retrieved using an inversion method with an iteration algorithm and a twostream radiative transfer model. A method adopted to calculate snow particle terminal velocity. Finally, snowfall rate is computed by numerically solving a complex integral. The SFR products are being used mainly in two communities: hydrology and weather forecast. Global blended precipitation products traditionally do not include snowfall derived from satellites because such products were not available operationally in the past. The ATMS and AMSU/MHS SFR now provide the winter precipitation information for these blended precipitation products. Weather forecasters mainly rely on radar and station observations for snowfall forecast. The SFR products can fill in gaps where no conventional snowfall data are available to forecasters. The products can also be used to confirm radar and gauge snowfall data and increase forecasters' confidence in their prediction

    Strategies for Searching Video Content with Text Queries or Video Examples

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    The large number of user-generated videos uploaded on to the Internet everyday has led to many commercial video search engines, which mainly rely on text metadata for search. However, metadata is often lacking for user-generated videos, thus these videos are unsearchable by current search engines. Therefore, content-based video retrieval (CBVR) tackles this metadata-scarcity problem by directly analyzing the visual and audio streams of each video. CBVR encompasses multiple research topics, including low-level feature design, feature fusion, semantic detector training and video search/reranking. We present novel strategies in these topics to enhance CBVR in both accuracy and speed under different query inputs, including pure textual queries and query by video examples. Our proposed strategies have been incorporated into our submission for the TRECVID 2014 Multimedia Event Detection evaluation, where our system outperformed other submissions in both text queries and video example queries, thus demonstrating the effectiveness of our proposed approaches
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