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REVIEW 4 major objections 5 minor 22 references

The Autonomous Software Stack of the FRED-003C: The Development That Led to Full-Scale Autonomous Racing

T0 review · 4 major / 5 minor · reviewed 2026-08-16 · deepseek-v4-flash

Pith's one-line read The paper claims that a modular autonomous racing stack—particle-filter mapping with graph optimisation, LiDAR-camera cone fusion, reward-based centerline planning, and blended kinematic steering—is enough to race, as shown by a…

desk verdict A credible student-engineering paper whose central planning equation appears to be misprinted; worth reviewing after corrections. read the letter →

arxiv 2504.18439 v1 pith:7ROIMM3E submitted 2025-04-25 cs.RO

classification cs.RO
keywords autonomousracingFormulaStudentDriverlesssimultaneouslocalisationandmappingLiDAR-camerafusionconedetectioncenterlineplanningvelocityprofilelateralcontrol
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

The paper presents the autonomous software stack of a Formula Student race car and argues that the stack is enough to race competitively at the 2023 Formula Student Germany electric-driverless event, where it placed third with a fastest trackdrive lap of 41.02 s. The authors' case is that a modular pipeline—particle-filter mapping with graph optimisation, LiDAR-camera cone detection and colour classification, reward-based centerline planning, and a lightweight blended lateral controller—can deliver this performance without dynamic model-based control or heavy optimisation solvers. The paper backs the claim with lap-time and path-tracking data, a comparison of trajectory smoothing methods, and simulated controller comparisons. If the central claim is right, this is a practical template for student teams and a plausible starting point for full-scale autonomous racing development.

What carries the argument

The central mechanism is the centreline search over midpoints of a Delaunay triangulation of the detected cones. At each step the planner scores candidate midpoints with a weighted sum of reward factors—track width, cone colour, angle change, spacing, and a predictive-model term—and greedily selects the highest-scoring midpoint; the track-width reward is designed to keep the trajectory inside the 3–5 m band with a Gaussian transition instead of a hard rule. A secondary mechanism is the curvature-dependent steering blend: as path curvature grows, more weight shifts toward the geometric look-ahead law, and as the corner exits, weight shifts back to the kinematic cross-track-error law, which the paper reports reduces overshoot in tight corners. The trajectory smoothing (moving average plus simplification) and $C^2$ cubic-spline fitting are what turn the discrete midpoint chain into a reference with low curvature variation.

What would settle it

Evaluate Equation (4) at $x=5$ from both sides: the middle branch gives $f(5)=1$, while the right branch gives $1.3\exp(-(2/0.4)^2/2)-0.3\approx 0.30$, so the printed reward jumps at the boundary it is supposed to smooth, and at $x=5.5$ it is about $-0.29$ even though the text describes 3–5 m as optimal. Plotting or instrumenting the planner's actual reward output on track segments wider than 5 m would settle whether the formula is a typo and whether the smoothing property really holds.

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Extended reading notes

Core claim

On the paper's own terms, the central discovery is that a deliberately modular, low-complexity stack can reach race performance. The state estimator combines FastSLAM-style particle filtering with pose-graph optimisation over landmark observation and pose motion residuals; the perception system detects track-bounding cones from LiDAR clusters and uses camera bounding boxes for colour classification and false-detection rejection; the planner searches the midpoints of a Delaunay triangulation of the cone map with a weighted reward function and then smooths, spline-fits, and velocity-profiles the resulting path; and the controller blends two kinematic steering laws with a curvature-dependent weight plus a yaw-damping term. The paper reports that this system gave the team its first podium at Formula Student Germany, with an average trackdrive lap of 41.30 s and a fastest lap of 41.02 s.

Load-bearing premise

The load-bearing premise is that the printed track-width reward function in Equation (4) matches the planner's real implementation, because as printed its right-hand Gaussian is centered at $x=3$ rather than $x=5$, making the reward discontinuous at 5 m and negative above about 5.9 m—which would contradict the paper's description of smooth promotion and penalisation around the 3–5 m optimal range.

Editorial extensions

If this is right

  • A complete, competitive driverless stack can be assembled from accessible methods—particle-filter SLAM, geometric controllers, and rule-based reward functions—without model predictive control or commercial optimisation solvers.
  • LiDAR-only perception with camera-supplemented colour classification is robust enough for competition, because the fusion step falls back to LiDAR whenever a projected cone lies outside the camera's field of view.
  • The reward-based centerline planner can build a drivable trajectory online from an unseen cone layout, and the smoothing-and-spline step can keep curvature variation low enough for high-speed lap times.
  • The velocity profile generated under dynamic constraints can be tracked with a simple longitudinal P controller and a blended steering law, consistent with the reported 41.02 s best lap.
  • The same architecture can serve as a springboard to full-scale autonomous racing, since the development path described in the paper continued beyond the Formula Student car.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • An editorial reading of the smoothing table is that the combined smoother's lap-time gain comes almost entirely from suppressing curvature variation (CVR drops from order $10^{-1}$ to $10^{-3}$), which suggests the effective objective the planner is optimising may be curvature smoothness rather than raw path shortness.
  • A reader wanting to reuse the stack should treat the printed Equation (4) as provisional: if the right-tail center is a typo for $x=5$, the reward is symmetric and the described behavior follows; if not, the planner needs the 5 m boundary case audited before relying on wide-track sections.
  • The paper's lateral-controller comparison is reported only in simulation, so the on-track 41.02 s lap cannot by itself isolate the contribution of the combined controller; an on-vehicle ablation of the three steering laws on the same track would separate those effects.
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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

4 major / 5 minor

Summary. This paper describes the autonomous software stack of the BME Formula Racing Team's FRED-003C vehicle used in the Formula Student Driverless competition. The stack is organized into state estimation (a FastSLAM/Graph-SLAM hybrid and a LiDAR-inertial SLAM), perception (YOLOv5 camera detection, LiDAR clustering with intensity-based colour classification, and LiDAR-camera fusion), planning (Delaunay-triangulation-based centreline search with a reward function, smoothing, spline fitting, and velocity-profile optimization), and control (a blended Stanley/Pure Pursuit lateral controller with yaw damping and a P-controller for longitudinal actuation). The paper reports a third-place overall finish in the electric-driverless category at Formula Student Germany 2023, with an average trackdrive lap time of 41.30 s and a fastest lap of 41.02 s, and it presents simulation comparisons for the smoothing and control methods.

Significance. If the system description is accurate, the paper is a useful engineering reference for student autonomous-racing teams: it shows a complete, competition-validated pipeline, discusses practical tuning considerations, and compares design alternatives such as smoothing methods and lateral controllers. The paper's main strengths are its direct grounding in competition results and its honest reporting of limitations, such as the steady-state error of the longitudinal P-controller. However, several equations that are central to the described modules contain inconsistencies, notably Eq. (4), Eq. (2), and the FastSLAM resampling statement. As printed, the manuscript does not allow a reader to reproduce or verify the algorithms, even though the competition result provides credible evidence that a version of the system worked. These issues are correctable in revision.

major comments (4)
  1. [III-C, Eq. (4)] The reward function as printed cannot implement the behaviour described in the text. Both the x<3 and x>5 branches are the same Gaussian centred at x=3, so at the upper boundary of the intended optimal range the score jumps from exactly 1 at x=5 to 1.3*exp(-((5-3)/0.4)^2/2) - 0.3 ≈ -0.3 just above 5 m, and for all larger widths the score approaches -0.3. This contradicts the statement that the optimal track-width range is 3 to 5 m and the claim that the Gaussian acts as a smoothing term. Please correct the right-hand branch (presumably to centre it at x=5) or provide the actual reward parameters; without this, the printed planning algorithm is not the one that produced the reported lap times.
  2. [III-A2, Eq. (2)] In the pose-motion residual, the translational terms use v cos(pθ,prev + ω) and v sin(pθ,prev + ω), which imply that ω is the total heading change over the interval, but the third component subtracts 2ω from the orientation difference. No time step appears, and the factor of 2 is not explained. Please state whether ω is an angular velocity or a heading increment and define the residual consistently; as written, the graph-optimization objective is not mathematically well-defined.
  3. [III-D1, Table II and surrounding text] Table II reports that the combined controller has ITAE = 143.0 and RMS = 0.201 m, both worse than the Stanley controller with ITAE = 50.0 and RMS = 0.075 m, while the text claims that the combined controller 'leverages the strengths of both approaches' and achieves 'improved recovery characteristics.' If ITAE and RMS are standard error metrics for which lower is better, the table does not support the qualitative claim. Please define ITAE, explain why the combined controller is preferred despite its higher tracking error, or revise the claim so that the text and table are consistent.
  4. [III-A1, FastSLAM description] The paper states that 'resampling selects the highest weighing particle to output the corresponding map and pose.' Standard particle-filter resampling draws particles randomly with replacement according to their normalized weights; deterministically selecting the highest-weight particle would collapse the particle distribution and is not the FastSLAM algorithm as commonly understood. Please clarify whether the highest-weight particle is used only for output while resampling is performed in the standard way, or describe the actual resampling procedure used in the implementation.
minor comments (5)
  1. [IV, Results] The sentence 'For the first time in the team's history, Formula Student East and the overall third place...' is incomplete and is immediately followed by a rephrased duplicate ('In 2023 at FSG, the team also got Formula Student East and the overall third place...'). Remove the duplicate and fix the sentence.
  2. [III-D1, Eq. (7)] Please define all symbols and check units in Eq. (7); as written, θ_ss = m r_traj v / C_y (1 + l_F/l_R) does not obviously produce a dimensionless angle, and C_y is described as tire stiffness on the front axle without specifying units or whether rear-axle stiffness is needed.
  3. [III-C, Figure 7] The axes of Figure 7 are unlabeled. Add axis labels and numeric ticks consistent with Eq. (4) so that the reader can verify the plotted reward function.
  4. [III-D1, Eq. (13)] It is unclear how the yaw-damping term kd,yaw(rmeas - rtraj) enters the steering law; please specify whether it is added to Eq. (10) and how rmeas is obtained from the vehicle's sensors or estimator.
  5. [III-D1, stability discussion] The text says that the combined controller is stable because the Stanley and Pure Pursuit controllers are each stable, but stability of the individual controllers does not automatically imply stability of a velocity- and curvature-dependent convex combination; please either provide a supporting argument or soften the stability claim.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the paper is a system description validated by external competition results; no prediction reduces to its inputs by construction.

full rationale

The paper makes no first-principles prediction: it documents an existing autonomous racing stack and evaluates it by external competition results (third place and a 41.02 s fastest lap at Formula Student Germany 2023) plus internal simulations. No load-bearing derivation reduces to its own inputs by construction. The FastSLAM and Graph SLAM residuals in Eqs. (1)-(2) are standard pose and landmark error definitions; the LiDAR-camera fusion in Eq. (3) is a standard projective transformation; the planning reward in Eqs. (4)-(5) is a hand-specified cost used to generate a centerline, not a prediction of an outcome; and the control laws in Eqs. (6)-(12) are standard Stanley and Pure Pursuit formulas with tuning parameters. Tables I and II compare smoothing and control variants, but these are retrospective engineering evaluations, not fitted parameters renamed as predictions, and the competition lap time is not used to fit the compared parameters. Citations [2], [6], and [18]-[21] are external baseline and controller sources; the paper's references to its own A2RL experience are contextual motivation, not load-bearing justification. The only notable inconsistency is Eq. (4), whose right-tail Gaussian is centered at x = 3 instead of x = 5, creating a discontinuity and negative rewards above 5 m; this is a correctness and reproducibility defect, not circularity. Therefore the circularity score is 0.

Assumptions & free parameters 7 free parameters · 4 assumptions · 0 invented entities

The central claim depends on a number of hand-tuned parameters (reward weights, controller gains, look-ahead constants) whose values are not reported, and on domain assumptions about cone detectability, the vehicle kinematic model, the dynamic model for velocity planning, and calibration accuracy. No new physical entity is introduced.

free parameters (7)
  • Reward function weights Weight_i = not reported
    The midpoint reward in Eq. (5) is a weighted sum of factors (track width, cone color, angle change, distance, prediction), with weights chosen by hand. No values are given, and they determine the planned path.
  • Stanley controller ksoft = not reported
    In Eq. (6), ksoft is tuned to avoid oversensitivity at low speeds. Its value is not stated.
  • Pure Pursuit look-ahead Ld,min and kv = not reported
    Eq. (9) defines the look-ahead distance as Ld = Ld,min + kv*v; both are hand-tuned and not reported.
  • Blend parameters kmin, kmax, kref, kcurve = not reported
    Eq. (12) sets the Pure Pursuit weight as a function of curvature; the parameters are selected after assessing scenarios and are not reported.
  • Gaussian reward shape parameters (1.3, 0.3, 0.4) = 1.3, 0.3, 0.4
    Appear in Eq. (4) and are hand-picked. The right tail is likely mis-centered, so the effective parameters are uncertain.
  • Longitudinal P controller gain = not reported
    Section III.D.2 uses a P controller for throttle and brake without stating the gain.
  • Lateral yaw damping gain kd,yaw = not reported
    Eq. (13) models tire forces as active damping; the gain is tuned for the torque vectoring system and not reported.
assumptions (4)
  • domain assumption The track is bounded by color-coded cones that can be reliably detected and classified.
    The perception, SLAM, and planning pipeline all depend on cone detection and color classification; stated in Section III.B.
  • domain assumption The kinematic bicycle model and Stanley controller stability properties apply to the FRED-003C platform.
    Section III.D.1 relies on the kinematic model and stability arguments from [18] without validating them on this vehicle.
  • domain assumption The vehicle dynamic model used by the velocity profile solver is accurate enough to produce feasible speed commands.
    Section III.C uses a forward-backward solver [17] that requires accurate dynamic constraints; no validation of the model is provided.
  • domain assumption The LiDAR-camera extrinsic calibration is accurate and remains valid during racing.
    Sensor fusion in Eq. (3) assumes a rigid transformation; the paper does not describe calibration or in-situ validation.

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Cite this review

Pith. "Pith review of The Autonomous Software Stack of the FRED-003C: The Development That Led to Full-Scale Autonomous Racing." pith.science (2026). https://pith.science/paper/7ROIMM3E

@misc{pith2026250418439,
  author       = {Pith},
  title        = {Pith review of: The Autonomous Software Stack of the FRED-003C: The Development That Led to Full-Scale Autonomous Racing},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/7ROIMM3E}},
  note         = {Machine review of arXiv:2504.18439}
}
read the original abstract

Scientific development often takes place in the context of research projects carried out by dedicated students during their time at university. In the field of self-driving software research, the Formula Student Driverless competitions are an excellent platform to promote research and attract young engineers. This article presents the software stack developed by BME Formula Racing Team, that formed the foundation of the development that ultimately led us to full-scale autonomous racing. The experience we gained here contributes greatly to our successful participation in the Abu Dhabi Autonomous Racing League. We therefore think it is important to share the system we used, providing a valuable starting point for other ambitious students. We provide a detailed description of the software pipeline we used, including a brief description of the hardware-software architecture. Furthermore, we introduce the methods that we developed for the modules that implement perception; localisation and mapping, planning, and control tasks.

Figures

Figures reproduced from arXiv: 2504.18439 by the authors.

Figure 1
Figure 1. The perception sensor placement of the FRED-003C. The LiDAR [PITH_FULL_IMAGE:figures/full_fig_p001_1.png] view at source ↗
Figure 2
Figure 2. Block diagram depicting the hardware-software architecture of the autonomous system. The software pipeline can be divided into four parts; state [PITH_FULL_IMAGE:figures/full_fig_p002_2.png] view at source ↗
Figure 3
Figure 3. LiDAR point cloud segmented into ground points marked by blue, [PITH_FULL_IMAGE:figures/full_fig_p003_3.png] view at source ↗
Figures from the paper (8 more)
Figure 4
Figure 4. Figure 4: LiDAR cluster centers marked by green crosses are projected onto [PITH_FULL_IMAGE:figures/full_fig_p003_4.png]
Figure 7
Figure 7. Figure 7: The reward function of the track width property for a midpoint, [PITH_FULL_IMAGE:figures/full_fig_p004_7.png]
Figure 5
Figure 5. Figure 5: Delaunay triangulation, [PITH_FULL_IMAGE:figures/full_fig_p004_5.png]
Figure 9
Figure 9. Figure 9: The cubic spline is preferred because of its twice [PITH_FULL_IMAGE:figures/full_fig_p005_9.png]
Figure 8
Figure 8. Figure 8: Combined smoothing aligns cen￾ter points (black dots) with given vectors (red arrows) to minimize curvature variation [PITH_FULL_IMAGE:figures/full_fig_p005_8.png]
Figure 12
Figure 12. Figure 12: The kinematic model for a front-steering vehicle represented in the trajectory frame. its stability conditions analysed in [20] and [21]. We adopted the following formulation δpp = arctan  2 (lF + lR) sin α Ld  (8) where lF + lR represents the wheelbase and α denote…
Figure 13
Figure 13. Figure 13: The planned path, where circles represent cones bounding the [PITH_FULL_IMAGE:figures/full_fig_p006_13.png]
Figure 14
Figure 14. Figure 14: Controller data, showing the target wheel angle and velocity, and [PITH_FULL_IMAGE:figures/full_fig_p007_14.png]

Discussion (0). Continue with ORCID to comment.

Reference graph

Works this paper leans on

22 extracted references · 18 canonical work pages

  1. [1]

    F1/10: An open-source autonomous cyber-physical platform,

    M. O’Kelly, V . Sukhil, H. Abbas, J. Harkins, C. Kao, Y . V . Pant, R. Mangharam, D. Agarwal, M. Behl, P. Burgio, and M. Bertogna, “F1/10: An open-source autonomous cyber-physical platform,” 2019

  2. [2]

    AMZ Driverless: The Full Autonomous Racing System

    J. Kabzan, M. de la Iglesia Valls, V . Reijgwart, H. F. C. Hendrikx, C. Ehmke, M. Prajapat, A. B ¨uhler, N. Gosala, M. Gupta, R. Sivanesan et al. , “Amz driverless: The full autonomous racing system,” 2019. [Online]. Available: https://arxiv.org/abs/1905.05150

  3. [3]

    er.autopilot 1.0: The full autonomous stack for oval racing at high speeds,

    A. Raji, D. Caporale, F. Gatti, A. Giove, M. Verucchi, D. Malatesta, N. Musiu, A. Toschi, S. Popitanu, F. Bagni, M. Bosi, Liniger et al. , “er.autopilot 1.0: The full autonomous stack for oval racing at high speeds,” Field Robotics, vol. 4, no. 1, p. 99–137, Jan. 2024

  4. [4]

    Rules & documents

    F. S. Germany, “Rules & documents.” [Online]. Available: https: //www.formulastudent.de/fsg/rules/

  5. [5]

    The sense-think-act paradigm revisited,

    M. Siegel, “The sense-think-act paradigm revisited,” in 1st Interna- tional Workshop on Robotic Sensing, 2003. ROSE’ 03. , 2003

  6. [6]

    The software stack that won the formula student driverless competition,

    A. Alvarez, N. Denner, Z. Feng, D. Fischer, Y . Gao, L. Harsch, S. Herz, N. L. Large, B. Nguyen, C. Rosero, S. Schaefer et al., “The software stack that won the formula student driverless competition,”

  7. [7]

    Fastslam: a factored solution to the simultaneous localization and mapping problem,

    M. Montemerlo, S. Thrun, D. Koller, and B. Wegbreit, “Fastslam: a factored solution to the simultaneous localization and mapping problem,” in Eighteenth National Conference on Artificial Intelligence. USA: American Association for Artificial Intelligence, 2002

  8. [8]

    Fastslam 2.0: An improved particle filtering algorithm for simultaneous localization and mapping that provably converges,

    M. Montemerlo and S. Thrun, “Fastslam 2.0: An improved particle filtering algorithm for simultaneous localization and mapping that provably converges,”IEEE Rob. Autom., vol. 13, pp. 99–110, 01 2007

Show all 22 references
  1. [9]

    Implementation of a slam algorithm,

    V . ´Akos, “Implementation of a slam algorithm,” BSc Thesis, E¨otv¨os Lor ´and Tudom´anyegyetem, Informatikai Kar, Budapest, 2022. [Online]. Available: https://github.com/lafette21/thesis-bsc

  2. [10]

    Fast-lio2: Fast direct lidar-inertial odometry,

    W. Xu, Y . Cai, D. He, J. Lin, and F. Zhang, “Fast-lio2: Fast direct lidar-inertial odometry,” 2021

  3. [11]

    Limo-velo: A real-time, robust, centimeter- accurate estimator for vehicle localization and mapping under racing velocities,

    A. Huguet Segarra et al., “Limo-velo: A real-time, robust, centimeter- accurate estimator for vehicle localization and mapping under racing velocities,” B.S. thesis, Universitat Polit `ecnica de Catalunya, 2022

  4. [12]

    ultralytics/yolov5: v7.0 - yolov5 sota realtime instance segmentation,

    G. Jocher, A. Chaurasia, A. Stoken, J. Borovec, Y . Kwon, K. Michael, J. Fang, Z. Yifu, C. Wong, D. Montes et al., “ultralytics/yolov5: v7.0 - yolov5 sota realtime instance segmentation,” Zenodo, 2022

  5. [13]

    Fsoco: The formula student objects in context dataset,

    N. V ¨odisch, D. Dodel, and M. Sch ¨otz, “Fsoco: The formula student objects in context dataset,” SAE International Journal of Connected and Automated Vehicles, vol. 5, no. 12-05-01-0003, 2022

  6. [14]

    Increased accuracy for fast moving lidars: Correction of distorted point clouds,

    T. Renzler, M. Stolz, M. Schratter, and D. Watzenig, “Increased accuracy for fast moving lidars: Correction of distorted point clouds,” in 2020 IEEE International Instrumentation and Measurement Tech- nology Conference (I2MTC) , 2020, pp. 1–6

  7. [15]

    A slope-robust cascaded ground segmentation in 3d point cloud for autonomous vehicles,

    P. Narksri, E. Takeuchi, Y . Ninomiya, Y . Morales, N. Akai, and N. Kawaguchi, “A slope-robust cascaded ground segmentation in 3d point cloud for autonomous vehicles,” in 2018 21st International Conference on Intelligent Transportation Systems (ITSC) , 2018

  8. [16]

    Generalized-icp

    A. Segal, D. Haehnel, and S. Thrun, “Generalized-icp.” in Robotics: science and systems , vol. 2, no. 4. Seattle, W A, 2009, p. 435

  9. [17]

    An optimal complexity algorithm for minimum-time velocity planning,

    L. Consolini, M. Locatelli, A. Minari, and A. Piazzi, “An optimal complexity algorithm for minimum-time velocity planning,” Systems & Control Letters , vol. 103, pp. 50–57, 2017

  10. [18]

    Autonomous automobile trajectory tracking for off-road driving: Con- troller design, experimental validation and racing,

    G. M. Hoffmann, C. J. Tomlin, M. Montemerlo, and S. Thrun, “Autonomous automobile trajectory tracking for off-road driving: Con- troller design, experimental validation and racing,” in 2007 American control conference. IEEE, 2007, pp. 2296–2301

  11. [19]

    Path following controller for au- tonomous vehicles,

    ´Ad´am Domina and V . Tihanyi, “Path following controller for au- tonomous vehicles,” in 2019 IEEE International Conference on Con- nected Vehicles and Expo (ICCVE) , 2019, pp. 1–5

  12. [20]

    Analysis of robotic vehicle steering and controller delay,

    K. N. Murphy, “Analysis of robotic vehicle steering and controller delay,” in Fifth International Symposium on Robotics and Manufac- turing, 1994, pp. 631–636

  13. [21]

    Stability analysis of mobile robot path tracking,

    A. Ollero and G. Heredia, “Stability analysis of mobile robot path tracking,” in Proceedings 1995 IEEE/RSJ International Conference on Intelligent Robots and Systems. Human Robot Interaction and Cooperative Robots, vol. 3, 1995, pp. 461–466 vol.3

  14. [2022]

    Available: https://arxiv.org/abs/2210.10933

    [Online]. Available: https://arxiv.org/abs/2210.10933

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