Fast Exact Search in Hamming Space with Multi-Index Hashing

There is growing interest in representing image data and feature descriptors using compact binary codes for fast near neighbor search. Although binary codes are motivated by their use as direct indices (addresses) into a hash table, codes longer than 32 bits are not being used as such, as it was thought to be ineffective. We introduce a rigorous way to build multiple hash tables on binary code substrings that enables exact k-nearest neighbor search in Hamming space. The approach is storage efficient and straightforward to implement. Theoretical analysis shows that the algorithm exhibits sub-linear run-time behavior for uniformly distributed codes. Empirical results show dramatic speedups over a linear scan baseline for datasets of up to one billion codes of 64, 128, or 256 bits

Planning stable and efficient paths for articulated mobile robots on challenging terrains

An analytical strategy to generate stable paths for a reconfigurable vehicle while also meeting additional navigational objectives is herein proposed. The work is motivated by robots traversing over challenging terrains during search and rescue operations, such as those equipped with manipulator arms and/or flippers. The proposed solution looks at minimizing the length of the traversed path and the energy expenditure in changing postures, yet also accounts for additional constraints in terms of sensor visibility (i.e arm configurations close to those orthogonal to the horizontal global plane which can afford a wider sensor view) and traction (i.e. flipper angles that provide the largest trackterrain interaction area). The validity of the proposed planning approach is evaluated with a multitracked robot fitted with flippers and a range camera at the end of a manipulator arm while navigating over two challenging 3D terrain data sets: one in a mock-up urban search and rescue arena (USAR), and a second one from a publicly available quasi-outdoor rover testing facility (UTIAS)

Probabilistic stable motion planning with stability uncertainty for articulated vehicles on challenging terrains

© 2015, Springer Science+Business Media New York. A probabilistic stable motion planning strategy applicable to reconfigurable robots is presented in this paper. The methodology derives a novel statistical stability criterion from the cumulative distribution of a tip-over metric. The measure is dynamically updated with imprecise terrain information, localization and robot kinematics to plan safety-constrained paths which simultaneously allow the widest possible visibility of the surroundings by simultaneously assuming highest feasible vantage robot configurations. The proposed probabilistic stability metric allows more conservative poses through areas with higher levels of uncertainty, while avoiding unnecessary caution in poses assumed at well-known terrain sections. The implementation with the well known grid based A* algorithm and also a sampling based RRT planner are presented. The validity of the proposed approach is evaluated with a multi-tracked robot fitted with a manipulator arm and a range camera using two challenging elevation terrains data sets: one obtained whilst operating the robot in a mock-up urban search and rescue arena, and the other from a publicly available dataset of a quasi-outdoor rover testing facility

Safety, effectiveness and economic evaluation of intra-operative radiation therapy: A systematic review

Background: Intra-operative radiation therapy (IORT) is the transfer of a single large radiation dose to the tumor bed during surgery with the final goal of improving regional tumor control. This study aimed to investigate the safety, effectiveness and economic evaluation of intra-operative radiation therapy. Methods: The scientific literature was searched in the main biomedical databases (Centre for Reviews and Dissemination, Cochrane Library and PubMed) up to March 2014. Two independent reviewers selected the papers based on pre-established inclusion criteria, with any disagreements being resolved by consensus. Data were then extracted and summarized in a structured form. Results from studies were analyzed and discussed within a descriptive synthesis. Results: Sixteen studies met the inclusion criteria. It seems that outcomes from using intraoperative radiation therapy can be considered in various kinds of cancers like breast, pancreatic and colorectal cancers. The application of this method may provide significant survival increase only for colorectal cancer, but this increase was not significant for other types of cancer. This technology had low complications; and it is relatively safe. Using intra-operative radiation therapy could potentially be accounted as a cost-effective strategy for controlling and managing breast cancer. Conclusion: According to the existing evidences, that are the highest medical evidences for using intra-operative radiation therapy, one can generally conclude that intra-operative radiation therapy is considered as a relatively safe and cost-effective method for managing early-stage breast cancer and it can significantly increase the survival of patients with colorectal cancer. Also, the results of this study have policy implications with respect to the reimbursement of this technology