In computer-assisted orthopedic surgery (CAOS), accurate pre-operative to intra-operative bone registration is an essential and critical requirement for providing navigational guidance. This registration process is challenging since the intra-operative 3D points are sparse, only partially overlapped with the pre-operative model, and disturbed by noise and outliers. The commonly used method in current state-of-the-art orthopedic robotic system is bony landmarks based registration, but it is very time-consuming for the surgeons. To address these issues, we propose a novel partial-to-full registration framework based on gradient-SDF for CAOS. The simulation experiments using bone models from publicly available datasets and the phantom experiments performed under both optical tracking and electromagnetic tracking systems demonstrate that the proposed method can provide more accurate results than standard benchmarks and be robust to 90% outliers. Importantly, our method achieves convergence in less than 1 second in real scenarios and mean target registration error values as low as 2.198 mm for the entire bone model. Finally, it only requires random acquisition of points for registration by moving a surgical probe over the bone surface without the need for correspondences, thus showing significant potential clinical value. The code of the framework is available*.

The interconnect plays a key role in both the cost and performance of large-scale HPC systems. The cost of future high-bandwidth electronic interconnects mushrooms due to expensive optical transceivers needed between electronic switches. We describe a potentially cheaper and more power-efficient approach to building high-performance interconnects. Through empirical analysis of HPC applications, we find that the bulk of inter-processor communication (barring collectives) is bounded in degree and changes very slowly or never. Thus we propose a two-network interconnect: An Optical Circuit Switching (OCS) network handling long-lived bulk data transfers, using optical switches; and a secondary lower-bandwidth Electronic Packet Switching (EPS) network. An OCS could be significantly cheaper, as it uses fewer optical transceivers than an electronic network. Collectives and transient communication packets traverse the electronic network. We present compiler techniques and dynamic run-time policies, using this two-network interconnect. Simulation results show that our approach provides high performance at low cost.