Anticipatory Robot Control for a Partially Observable Environment Using Episodic Memories

This paper explains an episodic-memory based approach for computing anticipatory robot behavior in a partially observable environment. Inspired by biological findings on the mammalian hippocampus, here, the episodic memories retain a sequence of experienced observation, behavior, and reward. Incorporating multiple machine learning methods, this approach attempts to help reducing the computational burden of the partially observable Markov decision process (POMDP). In particular, the proposed computational reduction techniques include: 1) abstraction of the state space via temporal difference learning; 2) abstraction of the action space by utilizing motor schemata; 3) narrowing down the state space in terms of the goals by employing instance-based learning; 4) elimination of the value-iteration by assuming a unidirectional-linear-chaining formation of the state space; 5) reduction of the state-estimate computation by exploiting the property of the Poisson distribution; and 6) trimming the history length by imposing the cap on the number of episodes that are computed. Furthermore, claims 5) and 6) were empirically verified, and it was confirmed that the state estimation can be in fact computed in an O(n) time (where n is the number of the states), more efficient than a conventional Kalman-filter based approach of O(n2)

Anticipatory Robot Navigation by Simultaneously Localizing and Building a Cognitive Map

This paper presents a method for a mobile robot to construct and localize relative to a “cognitive map”, where the cognitive map is assumed to be a representational structure that encodes both spatial and behavioral information. The localization is performed by applying a generic Bayes filter. The cognitive map was implemented within a behavior-based robotic system, providing a new behavior that allows the robot to anticipate future events using the cognitive map. One of the prominent advantages of this approach is elimination of the pose sensor usage (e.g., shaft encoder, compass, GPS, etc.), which is known for its limitations and proneness to various errors. A preliminary experiment was conducted in simulation and its promising results are discussed

Usability Evaluation of an Automated Mission Repair Mechanism for Mobile Robot Mission Specification

This paper describes a usability study designed to assess ease of use, user satisfaction, and performance of a mobile robot mission specification system. The software under consideration, MissionLab, allows users to specify a robot mission as well as compile it, execute it, and control the robot in real-time. In this work, a new automated mission repair mechanism that aids users in correcting faulty missions was added to the system. This mechanism was compared to an older version in order to better inform the development process, and set a direction for future improvements in usability

Three-dimensional Assessment of Femoral Head Coverage in Normal and Dysplastic Hips: A Novel Method

The acetabular coverage of the femoral head has been assessed in two-dimensions as the projected covered area or the covered angle on plain radiographs. We present a novel method of the three-dimensional assessment of femoral head coverage obtained by evaluating the covered volume of the femoral head in both normal and dysplastic hips. We also assessed the covered angles on the vertical slices passing through the center of the femoral head. The mean covered volume of the femoral head was 57.4% in normal hips and 26.6% in dysplastic hips. In dysplastic hips, the L-CE, A-CE, and P-CE angles were 7.7°, 21.8°, and 95.8°, respectively, while the acetabular angle was 27.5°. In normal hips, the CE angles were 34.0°, 56.8°, and 109.4°, respectively, while the acetabular angle was 7.2°. Our study suggests the usefulness of a novel 3D assessment for acetabular coverage of the femoral head. This assessment provided the precise 3D information necessary to diagnose hip dysplasia and assess the deficiency of acetabular coverage in these patients. Moreover, we may detect a cut-off between normal and dysplastic hips in the 3D assessment by assessing a large number of dysplastic hips both morphologically and using the new assessment

Integrated Mission Specification and Task Allocation for Robot Teams - Design and Implementation

As the capabilities, range of missions, and the size of robot teams increase, the ability for a human operator to account for all the factors in these complex scenarios can become exceedingly difficult. Our previous research has studied the use of case-based reasoning (CBR) tools to assist a user in the generation of multi-robot missions. These tools, however, typically assume that the robots available for the mission are of the same type (i.e., homogeneous). We loosen this assumption through the integration of contract-net protocol (CNP) based task allocation coupled with a CBR-based mission specification wizard. Two alternative designs are explored for combining case-based mission specification and CNP-based team allocation as well as the tradeoffs that result from the selection of one of these approaches over the other

Relationship between the Hip Abductor Muscles and Abduction Strength in Patients with Hip Osteoarthritis

This study aimed to determine which muscle the gluteus maximus, gluteus medius, gluteus minimus (Gmin), or tensor fasciae latae (TFL) contributes most to hip abduction strength and to identify effective sites for cross-sectional area (CSA) Gmin and TFL measurement in hip osteoarthritis (OAhip) patients. Twenty-eight patients with OAhip were included. The muscle CSA and volume were determined using magnetic resonance imaging. Peak isometric strength was determined using hand-held dynamometry. Muscle volumes were normalized to the total muscle volume of hip abductors. Multiple regression analysis was performed. The difference between the CSA of Gmin and TFL was calculated, and correlations with volume and muscle strength were determined. Gmin volume was related to abductor muscle strength (p=0.042). The peak CSA of the Gmin correlated with muscle volume and strength. The CSA of the TFL correlated with volume, with no difference between the CSA of the most protruding part of the lesser trochanter and peak CSA. Gmin volume was strongly related to abductor muscle strength. Peak CSA is a useful parameter for assessing the CSA of the Gmin among patients with OAhip. The CSA of the TFL should be measured at the most protruding part of the lesser trochanter

Multi-Robot User Interface Modeling

This paper investigates the problem of user interface design and evaluation for autonomous teams of heterogeneous mobile robots. We explore an operator modeling approach to multi-robot user interface evaluation. Specifically the authors generated GOMS models, a type of user model, to investigate potential interface problems and to guide the interface development process. Results indicate that our interface design changes improve the usability of multi-robot mission generation substantially. We conclude that modeling techniques such as GOMS can play an important role in robotic interface development. Moreover, this research indicates that these techniques can be performed in an inexpensive and timely manner, potentially reducing the need for costly and demanding usability studies

An Empirical Evaluation of Context-Sensitive Pose Estimators in an Urban Outdoor Environment

When a mobile robot is executing a navigational task in an urban outdoor environment, accurate localization information is often essential. The difficulty of this task is compounded by sensor drop-out and the presence of non-linear error sources over the span of the mission. We have observed that certain motions of the robot and environmental conditions affect pose sensors in different ways. In this paper, we propose a computational method for localization that systematically integrates and evaluates contextual information that affects the quality of sensors, and utilize the information in order to improve the output of sensor fusion. Our method was evaluated in comparison with conventional probabilistic localization methods (namely, the extended Kalman filter and Monte Carlo localization) in a set of outdoor experiments. The results of the experiment are also reported in this paper

HBD1 protein with a tandem repeat of two HMG-box domains is a DNA clip to organize chloroplast nucleoids in Chlamydomonas reinhardtii

葉緑体核様体をコンパクトに折りたたむ「DNAクリップ」の発見 --ミトコンドリアとも共通する普遍的なしくみの解明--. 京都大学プレスリリース. 2021-05-12.Compaction of bulky DNA is a universal issue for all DNA-based life forms. Chloroplast nucleoids (chloroplast DNA–protein complexes) are critical for chloroplast DNA maintenance and transcription, thereby supporting photosynthesis, but their detailed structure remains enigmatic. Our proteomic analysis of chloroplast nucleoids of the green alga Chlamydomonas reinhardtii identified a protein (HBD1) with a tandem repeat of two DNA-binding high mobility group box (HMG-box) domains, which is structurally similar to major mitochondrial nucleoid proteins transcription factor A, mitochondrial (TFAM), and ARS binding factor 2 protein (Abf2p). Disruption of the HBD1 gene by CRISPR-Cas9–mediated genome editing resulted in the scattering of chloroplast nucleoids. This phenotype was complemented when intact HBD1 was reintroduced, whereas a truncated HBD1 with a single HMG-box domain failed to complement the phenotype. Furthermore, ectopic expression of HBD1 in the mitochondria of yeast Δabf2 mutant successfully complemented the defects, suggesting functional similarity between HBD1 and Abf2p. Furthermore, in vitro assays of HBD1, including the electrophoretic mobility shift assay and DNA origami/atomic force microscopy, showed that HBD1 is capable of introducing U-turns and cross-strand bridges, indicating that proteins with two HMG-box domains would function as DNA clips to compact DNA in both chloroplast and mitochondrial nucleoids

Vagus-macrophage-hepatocyte link promotes post-injury liver regeneration and whole-body survival through hepatic FoxM1 activation

The mechanisms underlying the regenerative capacity of the liver are not fully understood. Here, the authors show that the acute regenerative response to liver injury in mice is regulated by the communication involving the vagus nerve, macrophages, and hepatocytes, leading to hepatic FoxM1 activation and promotion of overall survival