Planning humanlike actions in blending spaces

Abstract—We introduce an approach for enabling sampling-based planners to compute motions with humanlike appearance. The proposed method is based on a space of blendable example motions collected by motion capture. This space is explored by a sampling-based planner that is able to produce motions around obstacles while keeping solutions similar to the original examples. The results therefore largely maintain the humanlike characteristics observed in the example motions. The method is applied to generic upper-body actions and is complemented by a locomotion planner that searches for suitable body placements for executing upper-body actions successfully. As a result, our overall multi-modal planning method is able to automatically coordinate whole-body motions for action execution among obstacles, and the produced motions remain similar to example motions given as input to the system. I

Designing antibiotic cycling strategies by determining and understanding local adaptive landscapes

The evolution of antibiotic resistance among bacteria threatens our continued ability to treat infectious diseases. The need for sustainable strategies to cure bacterial infections has never been greater. So far, all attempts to restore susceptibility after resistance has arisen have been unsuccessful, including restrictions on prescribing [1] and antibiotic cycling [2,3]. Part of the problem may be that those efforts have implemented different classes of unrelated antibiotics, and relied on removal of resistance by random loss of resistance genes from bacterial populations (drift). Here, we show that alternating structurally similar antibiotics can restore susceptibility to antibiotics after resistance has evolved. We found that the resistance phenotypes conferred by variant alleles of the resistance gene encoding the TEM {\beta}-lactamase (blaTEM) varied greatly among 15 different {\beta}-lactam antibiotics. We captured those differences by characterizing complete adaptive landscapes for the resistance alleles blaTEM-50 and blaTEM-85, each of which differs from its ancestor blaTEM-1 by four mutations. We identified pathways through those landscapes where selection for increased resistance moved in a repeating cycle among a limited set of alleles as antibiotics were alternated. Our results showed that susceptibility to antibiotics can be sustainably renewed by cycling structurally similar antibiotics. We anticipate that these results may provide a conceptual framework for managing antibiotic resistance. This approach may also guide sustainable cycling of the drugs used to treat malaria and HIV

Multi-Modal Planning for Humanlike Motion Synthesis using Motion Capture

Planning the motions of a virtual character with high quality and control is a difficult challenge. Striking a balance between these two competing properties makes the problem particularly complex. While data-driven approaches produce high quality results due to the inherent realism of human motion capture data, planning algorithms are able to solve general continuous problems with a high degree of control. This dissertation addresses this overall problem with new techniques that combine the two approaches.Three main contributions are proposed. First, a simple and efficient motion capture segmentation mechanism is proposed based on geometric features that introduces semantic information for organizing a motion capture database into a motion graph. The obtained feature-based motion graph has less nodes and increased connectivity, which leads to improved searches in speed and coverage when compared to the standard approach. In addition, feature-based motion graphs enable a novel inverse branch kinematic deformation technique to be executed efficiently, allowing solution branches to be deformed towards precise goals without degrading the quality of the results.Second, in order to address speed of computation, precomputed motion maps are introduced for the interactive search and synthesis of locomotion sequences from unstructured feature-based motion graphs. Unstructured graphs can be successfully handled by relying on multiple maps and a search mechanism with backtracking information, which eliminates the need of manually creating fully connected move graphs. Precomputed motion maps can simultaneously search and execute motions in environments with many obstacles at interactive rates.Finally, a multi-modal data-driven framework is proposed for task-oriented human-like motion planning, which combines data-driven methods with parameterized motion skills in order to achieve human motions that are realistic and that have a high degree of controllability. The multi-modal planner relies on feature-based motion graphs for achieving a high-quality locomotion skill and integrates generic, task-specific data-based or algorithmic motion primitive skills for precise upper-body manipulation and action planning. The approach includes a multi-modal search method where primitive motion skills compete for contributing to the final solution.As a result, the overall proposed framework provides a high degree of control and, at the same time, retains the realism and human-likeness of motion capture data. Several examples are presented for synthesizing complex motions such as walking through doors, relocating books on shelves, etc

Parallel Inverse Kinematics for Multithreaded Architectures

In this article, we present a parallel prioritized Jacobian-based inverse kinematics algorithm for multithreaded architectures. We solve damped least squares inverse kinematics using a parallel line search by identifying and sampling critical input parameters. Parallel competing execution paths are spawned for each parameter in order to select the optimum that minimizes the error criteria. Our algorithm is highly scalable and can handle complex articulated bodies at interactive frame rates. We show results on complex skeletons consisting of more than 600 degrees of freedom while being controlled using multiple end effectors. We implement the algorithm both on multicore and GPU architectures and demonstrate how the GPU can further exploit fine-grain parallelism not directly available on a multicore processor. Our implementations are 10 to 150 times faster compared to a state-of-the-art serial implementation while providing higher accuracy. We also demonstrate the scalability of the algorithm over multiple scenarios and explore the GPU implementation in detail

The antibiotics used to characterize adaptive landscapes.

<p>While not a comprehensive listing of all β-lactam antibiotics, this set contains many heavily used antibiotics and provides good general coverage of β-lactams.</p

Example of one possible outcome from antibiotic cycling.

<p>These diagrams show that by alternating the antibiotics cefepime, ceftazidime, and cefprozil susceptibility to those antibiotics can be restored in bacterial populations expressing variant alleles present in TEM-50 adaptive landscapes. 2a. (Top left) The TEM-50 adaptive landscape in cefepime. Yellow peaks indicate the adjacent alleles that are important during cefepime selection. 2b. (Top right) The TEM-50 adaptive landscape in ceftazidime. Orange peaks indicate the adjacent alleles that are important during ceftazidime selection. 2c. (Bottom left) The TEM-50 adaptive landscape in cefprozil. Red peaks indicate the adjacent alleles that are important during cefprozil selection. 2d. (Bottom right) Composite cycle: The yellow arrow indicates the direction of selection in the presence of cefepime. The red arrows indicate the direction of selection in the presence of cefprozil. The orange arrow indicates the direction of selection in the presence of ceftazidime. Rotation of these antibiotics results in cyclical renewal of antibiotic susceptibility.</p

Constructs containing all possible combinations of the four mutations found in <i>bla</i>_TEM-50 and <i>bla</i>_TEM-85.

<p>Constructs containing all possible combinations of the four mutations found in <i>bla</i>_TEM-50 and <i>bla</i>_TEM-85.</p

Adaptive landscapes of TEM-85.

<p>These diagrams show the pathways through which the <i>bla</i>_TEM-85 can evolve in a single antibiotic. 1a. (Left) The TEM-85 adaptive landscape in cefotaxime with pathways to TEM-85 indicated. 1b. (Right) The TEM-85 adaptive landscape in ceftazidime with pathways to TEM-85 indicated.</p