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FusionCore: Multi-Context Fusion Approaches

Updated 4 July 2026
  • FusionCore is a shared name for three distinct systems: a prototype operator-fusion method for state-space models, a 23-state UKF-based ROS 2 sensor fusion package, and a laser-driven nuclear fusion micro-reactor concept.
  • In operator fusion, FusionCore reduces DRAM round-trips and enhances on-chip reuse by fusing tensor operations via entropy-driven scheduling and Hadamard reparameterization.
  • In robotics and nuclear applications, FusionCore improves state estimation with adaptive bias correction in a 23-state UKF and proposes novel nano-rod designs for efficient non-thermal fusion.

FusionCore is a shared name used in recent literature for three technically unrelated systems: a prototype operator-fusion methodology for selective state space models, presented as COREY; an open-source ROS 2 sensor-fusion package centered on a 23-state Unscented Kalman Filter; and a laser-driven mixed-fuel nuclear fusion micro-reactor concept based on nanostructured fuel targets (Ma et al., 12 Apr 2026, Kharwar, 24 May 2026, Ruhl et al., 2022). The common label therefore denotes neither a single framework nor a unified research program. Instead, it identifies distinct proposals in sequence-model systems, robotic state estimation, and pulsed fusion engineering.

1. Disambiguation and nomenclature

In the sequence-modeling literature, the term appears in the detailed description of COREY as the “FusionCore operator-fusion methodology (COREY),” a prototype framework for selective state space models (SSMs) of the Mamba family. Its central concern is memory-bandwidth-limited inference caused by fragmented kernels and repeated intermediate tensor materialization (Ma et al., 12 Apr 2026).

In robotics, FusionCore denotes an open-source ROS 2 package that fuses IMU, wheel encoder odometry, GPS, and Visual SLAM pose into a single 100 Hz odometry stream using a 23-state UKF. The package includes explicit gyroscope, accelerometer, and wheel-encoder yaw-rate bias estimation, native GPS handling, outlier gating, and adaptive covariance estimation (Kharwar, 24 May 2026).

In nuclear-fusion research, FusionCore denotes a laser-driven micro-reactor concept introduced by Ruhl and Korn. In that proposal, the fuel itself forms both the fusion “catcher” and an embedded nano-accelerator, with nanoscopic rods driven by ultra-short UV–VUV laser pulses to generate non-thermal ion distributions at near-solid density (Ruhl et al., 2022).

A common misconception would be to treat these as variants of one platform. The cited works instead use the same name for separate domain-specific constructions.

2. FusionCore in selective state space models: operator fusion, entropy, and Hadamard reparameterization

For selective SSMs, the baseline recurrence is written per time step tt as

ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,

yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.

These updates are linear-time in sequence length LL, i.e. O(L)O(L), which is attractive for long-context modeling. The practical bottleneck described in COREY is not asymptotic complexity but kernel fragmentation: pointwise multiply, scan, and reduction often become separate kernels, forcing repeated reads and writes of intermediate tensors to global memory. The stated motivation for FusionCore is therefore to fuse chains of operators into single kernels, reduce DRAM round-trips, increase on-chip reuse, and shift the critical path back toward compute (Ma et al., 12 Apr 2026).

The runtime scheduling signal is activation entropy. Given an activation tensor ZZ with NN values, a fixed-width KK-bin histogram yields counts countk\mathrm{count}_k and empirical probabilities pk=countk/Np_k=\mathrm{count}_k/N. The Shannon entropy estimate is

ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,0

and the prototype scheduler normalizes it as

ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,1

Prototype defaults are ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,2, ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,3, and EMA smoothing

ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,4

with ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,5 (Ma et al., 12 Apr 2026).

Candidate fusion regions ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,6 are scored by combining normalized entropy, arithmetic intensity, and estimated memory traffic:

ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,7

Regions with ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,8 and satisfying resource constraints are fused. The reported scheduler weights are ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,9, with entropy thresholds yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.0 and default yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.1. After boundary selection, tile sizes are chosen by mapping normalized entropy to the range yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.2 and rounding to the nearest yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.3:

yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.4

Higher-entropy regions therefore receive larger tiles, while lower-entropy regions receive smaller tiles to reduce register pressure (Ma et al., 12 Apr 2026).

The second mechanism is Hadamard reparameterization. Let yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.5 be a normalized Hadamard matrix with yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.6. For an original projection yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.7, COREY inserts an yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.8 pair:

yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.9

Defining LL0 and LL1 preserves exact function while mixing coordinates. The description states that this fused reparameterization increases histogram entropy, flattens peaks, and reduces coordinate LL2 outliers by up to a LL3 factor through the bound LL4 (Ma et al., 12 Apr 2026).

3. Fused-kernel design and prototype results for COREY

The fused-kernel design is specified as a single memory-pass pipeline: load a tile of input activations into on-chip shared or SRAM memory; apply the absorbed Hadamard rotation via LL5; execute linear projections, elementwise updates, and selective scan contributions; update and materialize the selective SSM state LL6; and write the final output back to global memory. Fusion groups are admitted only if per-group resource constraints satisfy LL7, LL8, and occupancy LL9 (Ma et al., 12 Apr 2026).

Empirical results are reported from a Python-level prototype with synthetic heavy-tailed activations, not from real GPU kernels. In FP16 prototype measurements over five runs, the “Short” bucket reports latency O(L)O(L)0 ms, throughput O(L)O(L)1 k tok/s, and DRAM O(L)O(L)2 B/token for No Fusion; O(L)O(L)3 ms, O(L)O(L)4 k tok/s, and O(L)O(L)5 B/token for Static Fusion; and O(L)O(L)6 ms, O(L)O(L)7 k tok/s, and O(L)O(L)8 B/token for Ours. In the “Medium” bucket, the corresponding values are O(L)O(L)9 ms, ZZ0 k tok/s, and ZZ1 B/token; ZZ2 ms, ZZ3 k tok/s, and ZZ4 B/token; and ZZ5 ms, ZZ6 k tok/s, and ZZ7 B/token. In the “Long” bucket, they are ZZ8 ms, ZZ9 k tok/s, and NN0 B/token; NN1 ms, NN2 k tok/s, and NN3 B/token; and NN4 ms, NN5 k tok/s, and NN6 B/token. In the “Ultra-long” bucket, they are NN7 ms, NN8 k tok/s, and NN9 B/token; KK0 ms, KK1 k tok/s, and KK2 B/token; and KK3 ms, KK4 k tok/s, and KK5 B/token, respectively (Ma et al., 12 Apr 2026).

The summary interpretation in the source is that FusionCore reduces DRAM bytes per token by approximately KK6–KK7 relative to static fusion, with corresponding latency and throughput gains that increase with sequence length. Low-bit experiments are reported only as a diagnostic stability proxy. In the ultra-long bucket under W4A8, the internal proxy is KK8 for No Fusion, KK9 for Static Fusion, and countk\mathrm{count}_k0 for Ours; the source describes this as a reduction of about countk\mathrm{count}_k1 versus static fusion at matched latency, while explicitly stating that checkpoint-level validation remains to be done (Ma et al., 12 Apr 2026).

4. FusionCore in ROS 2: the 23-state UKF architecture

The robotics FusionCore is built around a single, continuous-time twelve-parameter kinematic or dynamic model augmented with eleven bias states, for a total of countk\mathrm{count}_k2 states. The state vector is

countk\mathrm{count}_k3

The components represent ENU position countk\mathrm{count}_k4, a body-to-ENU orientation quaternion countk\mathrm{count}_k5, body-frame linear velocity countk\mathrm{count}_k6, body-frame angular velocity countk\mathrm{count}_k7, body-frame linear acceleration countk\mathrm{count}_k8, gyroscope biases countk\mathrm{count}_k9, accelerometer biases pk=countk/Np_k=\mathrm{count}_k/N0, and a wheel-encoder yaw-rate bias pk=countk/Np_k=\mathrm{count}_k/N1 (Kharwar, 24 May 2026).

The continuous-time dynamics use IMU inputs pk=countk/Np_k=\mathrm{count}_k/N2 at approximately pk=countk/Np_k=\mathrm{count}_k/N3 Hz:

pk=countk/Np_k=\mathrm{count}_k/N4

pk=countk/Np_k=\mathrm{count}_k/N5

with

pk=countk/Np_k=\mathrm{count}_k/N6

The model is discretized at each IMU step with pk=countk/Np_k=\mathrm{count}_k/N7 s, using quaternion-exponential integration in

pk=countk/Np_k=\mathrm{count}_k/N8

This formulation places the inertial biases and the encoder yaw-rate bias inside the filter state rather than in external correction logic (Kharwar, 24 May 2026).

Measurement models are defined for multiple sensor paths. IMU updates are split into raw pk=countk/Np_k=\mathrm{count}_k/N9-DOF bias-and-gravity updates with

ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,00

where ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,01 in ENU, plus optional roll–pitch or roll–pitch–yaw updates from a magnetometer. Wheel encoders provide a ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,02-DOF body-frame velocity measurement

ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,03

along with zero-vertical pseudo-measurements ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,04 and ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,05. GPS position is handled through a loose-coupling model with ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,06 and covariance

ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,07

or direct ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,08 for gps_msgs/GPSFix. GPS Doppler contributes a ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,09-DOF ENU velocity update ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,10. VSLAM pose is fused as a ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,11-DOF update

ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,12

with covariance floors ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,13 m and ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,14 rad (Kharwar, 24 May 2026).

5. Bias estimation, gating, adaptation, and benchmark results in robotic odometry

A distinctive component is the online estimation of the wheel-encoder yaw-rate bias ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,15, which is initialized to zero with large prior variance and modeled as a random walk. When GPS heading is available, the cross-covariance between encoder ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,16 error and GPS-derived bearing innovation drives a Kalman update of ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,17. During GPS blackouts, the most recent estimate is subtracted from ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,18 before propagation to mitigate heading drift in coast mode (Kharwar, 24 May 2026).

Outlier rejection uses Mahalanobis ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,19 gating. For each innovation ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,20 with predicted innovation covariance ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,21,

ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,22

Default thresholds are given as ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,23, or ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,24 for fast paths. The explicit values listed are ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,25 for GPS position with ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,26, ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,27 for VSLAM pose with ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,28, ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,29 for heading-only with ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,30, ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,31 for encoder velocity with ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,32 and ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,33, and ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,34 for IMU with ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,35 and approximately ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,36. Sensor noise covariance is adapted from a sliding innovation window of ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,37 using

ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,38

with per-diagonal floors ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,39 to prevent collapse below configured minima (Kharwar, 24 May 2026).

GPS is handled natively by converting WGS84 latitude, longitude, and altitude to ENU about the first fix through PROJ, without an external navsat_transform or UTM zones. Lever-arm corrections use

ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,40

VSLAM integration accepts nav_msgs/Odometry inputs from any visual SLAM system. Large pose jumps caused by map reinitialization are gated by ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,41, and after vslam.reinit_n consecutive rejections, with default ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,42, the map-to-odom offset is re-anchored to the current filter state (Kharwar, 24 May 2026).

Evaluation on twelve full-length NCLT sequences of ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,43–ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,44 minutes uses Absolute Trajectory Error RMSE computed with EVO and SE3 alignment to RTK ground truth. FusionCore is compared against robot_localization EKF and UKF with matched gates. The reported sequence-wise results for FusionCore versus robot_localization EKF are: 2012-01-08, ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,45 m versus ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,46 m; 2012-02-04, ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,47 m versus ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,48 m; 2012-03-31, ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,49 m versus ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,50 m; 2012-05-11, ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,51 m versus ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,52 m; 2012-06-15, ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,53 m versus ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,54 m; 2012-08-20, ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,55 m versus ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,56 m; 2012-09-28, ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,57 m versus ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,58 m; 2012-10-28, ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,59 m versus ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,60 m; 2012-11-04, ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,61 m versus ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,62 m; 2012-12-01, ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,63 m versus ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,64 m; 2013-02-23, ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,65 m versus ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,66 m; and 2013-04-05, ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,67 m versus ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,68 m. FusionCore is stated to achieve lower ATE on ten of twelve sequences, with winning-sequence improvements ranging from ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,69 to ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,70, while the robot_localization UKF diverges numerically on all twelve runs (Kharwar, 24 May 2026).

The two losses are specifically attributed to a rare ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,71 minute GPS blackout beyond the ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,72 correction range and an adversarial cluster of gross GPS outliers at a blackout boundary. The source characterizes both as cases with “clear architectural fixes,” which suggests that the reported failure modes are localized rather than random (Kharwar, 24 May 2026).

6. FusionCore as a laser-driven mixed-fuel nuclear fusion micro-reactor

In the nuclear-fusion usage, FusionCore is a fully integrated micro-reactor in which nuclear fuel itself forms both the fusion catcher and an embedded nano-accelerator. The central structure is an array of cylindrical nano-rods of radius ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,73 nm and axial length ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,74–ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,75m, made of a high-ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,76 fuel matrix such as boron or lithium and loaded with lighter fuel ions such as protons, deuterons, tritium, or ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,77. The rods are separated by a distance ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,78 chosen for stable propagation of a circularly polarized UV/VUV laser pulse with wavelength ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,79–ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,80 nm, pulse duration ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,81–ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,82 fs, and intensity ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,83 (Ruhl et al., 2022).

The interaction model begins with rapid ionization of the rods, electron overheating and expulsion, and the formation of a positively charged cylinder whose radial Coulomb field accelerates the light ions. For species ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,84, the density is written as ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,85 with ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,86–ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,87, while the host-ion density is given as ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,88–ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,89. The laser field satisfies

ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,90

and must exceed the ionization threshold

ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,91

Inside a rod, the radial accelerating field is

ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,92

and the inter-rod gap must satisfy

ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,93

for stable propagation under the stated critical-density condition (Ruhl et al., 2022).

The non-thermal fuel distribution is modeled during the collisionless Coulomb-explosion phase by a light-ion Vlasov equation,

ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,94

with characteristics

ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,95

Shell decomposition of the initial rod produces a phase-space “ring” structure,

ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,96

and after the shell exits the rod, the ions stream ballistically with sharply peaked velocities. The source describes the resulting distribution as near-homogeneous in space and multi-peaked and non-Maxwellian in velocity, with peaks engineered to coincide with Gamow resonances of the selected fuel mixture (Ruhl et al., 2022).

The binary fusion rate between species ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,97 and ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,98 is

ht=Atht1+Btxt,h_t = A_t\,h_{t-1} + B_t\,x_t,99

In the delta-shell model,

yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.00

For many fuels, the cross section is approximated as constant over a velocity window, while the usual yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.01-factor parameterization is given by

yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.02

with

yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.03

The details list two example cycles: yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.04 with yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.05 and yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.06, and yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.07 with yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.08 and yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.09 (Ruhl et al., 2022).

For non-thermal operation, the Lawson form yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.10 is replaced by an effective path-length condition involving yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.11, with yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.12. The single-pulse burn fraction is then

yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.13

and the per-pulse yield and gain are

yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.14

with yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.15. The stated scaling argument is that yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.16 and yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.17, so the burn fraction and gain become largely independent of density at fixed rod geometry. The concluding summary claims a high burn fraction yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.18–yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.19 per pulse at near-solid densities and yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.20 in aneutronic regimes (Ruhl et al., 2022).

7. Limitations, engineering constraints, and comparative interpretation

Each FusionCore instance is framed in its source as a prototype or concept with explicit constraints. For COREY, the evaluation is a Python-level prototype over synthetic heavy-tailed activations, and low-bit results are reported only through a hand-crafted stability proxy rather than checkpoint-level quality measurements. This limits direct extrapolation to deployed Triton kernels, although the source explicitly notes future Triton integration as a single-pass kernel with shared-memory load, fused Hadamard or projection or elementwise or update stages, and global write-back (Ma et al., 12 Apr 2026).

For the ROS 2 FusionCore, numerical robustness is a central claim because the comparison robot_localization UKF diverges on all twelve NCLT runs. At the same time, the source isolates two cases where FusionCore loses to the EKF baseline and attributes them to specific operating conditions: a yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.21 minute GPS blackout and a cluster of gross GPS outliers at a blackout boundary. This suggests that the package is designed for fault-tolerant multimodal odometry, but not that it is immune to prolonged observability loss or adversarial measurement sequences (Kharwar, 24 May 2026).

For the micro-reactor concept, the source foregrounds engineering challenges rather than operational demonstration. Heat removal at average power densities of yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.22–yt=Ctht+Dtxt.y_t = C_t\,h_t + D_t\,x_t.23 is assigned to micro-channel cooling in or behind the nano-rod substrate; neutron shielding for neutronic cycles is assigned to Li–Pb blankets or polymer or boron-carbide layers; and the destruction of individual nano-rods on each shot is addressed by tape-drive or rotating-disc targets that continuously present fresh nanostructured areas to the laser focus. These are design proposals, not experimental validations, and the distinction is essential for interpreting the concept’s maturity (Ruhl et al., 2022).

Taken together, the three usages show that “FusionCore” functions as a high-level label for fusion in very different senses: operator fusion for SSM inference, probabilistic fusion of heterogeneous sensors, and physical fusion of nuclear fuel. The shared nomenclature is semantically suggestive, but the underlying mathematical objects, performance criteria, and validation regimes are entirely domain-specific.

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