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Target Defense against Sequentially Arriving Intruders: Algorithm for Agents with Dubins Dynamics

Pourghorban, Arman, Maity, Dipankar

arXiv.org Artificial Intelligence

We consider a variant of the target defense problem where a single defender is tasked to capture a sequence of incoming intruders. Both the defender and the intruders have non-holonomic dynamics. The intruders' objective is to breach the target perimeter without being captured by the defender, while the defender's goal is to capture as many intruders as possible. After one intruder breaches or is captured, the next appears randomly on a fixed circle surrounding the target. Therefore, the defender's final position in one game becomes its starting position for the next. We divide an intruder-defender engagement into two phases, partial information and full information, depending on the information available to the players. We address the capturability of an intruder by the defender using the notions of Dubins path and guarding arc. We quantify the percentage of capture for both finite and infinite sequences of incoming intruders. Finally, the theoretical results are verified through numerical examples using Monte-Carlo-type random trials of experiments.


Appendix for "3D Siamese Voxel-to-BEV Tracker for Sparse Point Clouds " A Overview

Neural Information Processing Systems

B, we provide specific network architecture and more details about the target center parameterization for the voxel-to-BEV target localization network. As shown in Figure 1, we illustrate the specific network structure. Then, we present the 2D network to aggregate features in the BEV space. Finally, we provide more details on the target center parameterization. We also use a concatenated skip connection to fuse low-level and high-level features.


Multi-Attacker Single-Defender Target Defense in Conical Environments

Pourghorban, Arman, Maity, Dipankar

arXiv.org Artificial Intelligence

We consider a variant of the target defense problem in a planar conical environment where a single defender is tasked to capture a sequence of incoming attackers. The attackers' objective is to breach the target boundary without being captured by the defender. As soon as the current attacker breaches the target or gets captured by the defender, the next attacker appears at the boundary of the environment and moves radially toward the target with maximum speed. Therefore, the defender's final location at the end of the current game becomes its initial location for the next game. The attackers pick strategies that are advantageous for the current as well as for future engagements between the defender and the remaining attackers. The attackers have their own sensors with limited range, using which they can perfectly detect if the defender is within their sensing range. We derive equilibrium strategies for all the players to optimize the capture percentage using the notions of capture distribution. Finally, the theoretical results are verified through numerical examples using Monte Carlo type random trials of experiments.



A Low-Cost, High-Speed, and Robust Bin Picking System for Factory Automation Enabled by a Non-Stop, Multi-View, and Active Vision Scheme

Fu, Xingdou, Miao, Lin, Ohnishi, Yasuhiro, Hasegawa, Yuki, Suwa, Masaki

arXiv.org Artificial Intelligence

Bin picking systems in factory automation usually face robustness issues caused by sparse and noisy 3D data of metallic objects. Utilizing multiple views, especially with a one-shot 3D sensor and "sensor on hand" configuration is getting more popularity due to its effectiveness, flexibility, and low cost. While moving the 3D sensor to acquire multiple views for 3D fusion, joint optimization, or active vision suffers from low-speed issues. That is because sensing is taken as a decoupled module from motion tasks and is not intentionally designed for a bin picking system. To address the problems, we designed a bin picking system, which tightly couples a multi-view, active vision scheme with motion tasks in a "sensor on hand" configuration. It not only speeds up the system by parallelizing the high-speed sensing scheme to the robot place action but also decides the next sensing path to maintain the continuity of the whole picking process. Unlike others focusing only on sensing evaluation, we also evaluated our design by picking experiments on 5 different types of objects without human intervention. Our experiments show the whole sensing scheme can be finished within 1.682 seconds (maximum) on CPU and the average picking complete rate is over 97.75%. Due to the parallelization with robot motion, the sensing scheme accounts for only 0.635 seconds in takt time on average.


Improving Extrinsics between RADAR and LIDAR using Learning

Jiang, Peng, Saripalli, Srikanth

arXiv.org Artificial Intelligence

LIDAR and RADAR are two commonly used sensors in autonomous driving systems. The extrinsic calibration between the two is crucial for effective sensor fusion. The challenge arises due to the low accuracy and sparse information in RADAR measurements. This paper presents a novel solution for 3D RADAR-LIDAR calibration in autonomous systems. The method employs simple targets to generate data, including correspondence registration and a one-step optimization algorithm. The optimization aims to minimize the reprojection error while utilizing a small multi-layer perception (MLP) to perform regression on the return energy of the sensor around the targets. The proposed approach uses a deep learning framework such as PyTorch and can be optimized through gradient descent. The experiment uses a 360-degree Ouster-128 LIDAR and a 360-degree Navtech RADAR, providing raw measurements. The results validate the effectiveness of the proposed method in achieving improved estimates of extrinsic calibration parameters.


Target Defense against Periodically Arriving Intruders

Pourghorban, Arman, Maity, Dipankar

arXiv.org Artificial Intelligence

We consider a variant of pursuit-evasion games where a single defender is tasked to defend a static target from a sequence of periodically arriving intruders. The intruders' objective is to breach the boundary of a circular target without being captured and the defender's objective is to capture as many intruders as possible. At the beginning of each period, a new intruder appears at a random location on the perimeter of a fixed circle surrounding the target and moves radially towards the target center to breach the target. The intruders are slower in speed compared to the defender and they have their own sensing footprint through which they can perfectly detect the defender if it is within their sensing range. Considering the speed and sensing limitations of the agents, we analyze the entire game by dividing it into partial information and full information phases. We address the defender's capturability using the notions of engagement surface and capture circle. We develop and analyze three efficient strategies for the defender and derive a lower bound on the capture fraction. Finally, we conduct a series of simulations and numerical experiments to compare and contrast the three proposed approaches.


Multicenter automatic detection of invasive carcinoma on breast whole slide images

Peyret, Rémy, Pozin, Nicolas, Sockeel, Stéphane, Kammerer-Jacquet, Solène-Florence, Adam, Julien, Bocciarelli, Claire, Ditchi, Yoan, Bontoux, Christophe, Depoilly, Thomas, Guichard, Loris, Lanteri, Elisabeth, Sockeel, Marie, Prévot, Sophie

arXiv.org Artificial Intelligence

Breast cancer is one of the most prevalent cancers worldwide and pathologists are closely involved in establishing a diagnosis. Tools to assist in making a diagnosis are required to manage the increasing workload. In this context, artificial intelligence (AI) and deep-learning based tools may be used in daily pathology practice. However, it is challenging to develop fast and reliable algorithms that can be trusted by practitioners, whatever the medical center. We describe a patch-based algorithm that incorporates a convolutional neural network to detect and locate invasive carcinoma on breast whole-slide images. The network was trained on a dataset extracted from a reference acquisition center. We then performed a calibration step based on transfer learning to maintain the performance when translating on a new target acquisition center by using a limited amount of additional training data. Performance was evaluated using classical binary measures (accuracy, recall, precision) for both centers (referred to as test reference dataset and test target dataset) and at two levels: patch and slide level. At patch level, accuracy, recall, and precision of the model on the reference and target test sets were 92.1\% and 96.3\%, 95\% and 87.8\%, and 73.9\% and 70.6\%, respectively. At slide level, accuracy, recall, and precision were 97.6\% and 92.0\%, 90.9\% and 100\%, and 100\% and 70.8\% for test sets 1 and 2, respectively. The high performance of the algorithm at both centers shows that the calibration process is efficient. This is performed using limited training data from the new target acquisition center and requires that the model is trained beforehand on a large database from a reference center. This methodology allows the implementation of AI diagnostic tools to help in routine pathology practice.


Target Defense against Sequentially Arriving Intruders

Pourghorban, Arman, Dorothy, Michael, Shishika, Daigo, Von Moll, Alexander, Maity, Dipankar

arXiv.org Artificial Intelligence

We consider a variant of the target defense problem where a single defender is tasked to capture a sequence of incoming intruders. The intruders' objective is to breach the target boundary without being captured by the defender. As soon as the current intruder breaches the target or gets captured by the defender, the next intruder appears at a random location on a fixed circle surrounding the target. Therefore, the defender's final location at the end of the current game becomes its initial location for the next game. Thus, the players pick strategies that are advantageous for the current as well as for the future games. Depending on the information available to the players, each game is divided into two phases: partial information and full information phase. Under some assumptions on the sensing and speed capabilities, we analyze the agents' strategies in both phases. We derive equilibrium strategies for both the players to optimize the capture percentage using the notions of engagement surface and capture circle. We quantify the percentage of capture for both finite and infinite sequences of incoming intruders.