Hierarchical path planning from speech instructions with spatial concept-based topometric semantic mapping.

Assisting individuals in their daily activities through autonomous mobile robots is a significant concern, especially for users without specialized knowledge. Specifically, the capability of a robot to navigate to destinations based on human speech instructions is crucial. Although robots can take different paths toward the same objective, the shortest path is not always the most suitable. A preferred approach would be to accommodate waypoint specifications flexibly for planning an improved alternative path even with detours. Furthermore, robots require real-time inference capabilities. In this sense, spatial representations include semantic, topological, and metric-level representations, each capturing different aspects of the environment. This study aimed to realize a hierarchical spatial representation using a topometric semantic map and path planning with speech instructions by including waypoints. Thus, we present a hierarchical path planning method called spatial concept-based topometric semantic mapping for hierarchical path planning (SpCoTMHP), which integrates place connectivity. This approach provides a novel integrated probabilistic generative model and fast approximate inferences with interactions among the hierarchy levels. A formulation based on "control as probabilistic inference" theoretically supports the proposed path planning algorithm. We conducted experiments in a home environment using the Toyota human support robot on the SIGVerse simulator and in a lab-office environment with the real robot Albert. Here, the user issues speech commands that specify the waypoint and goal, such as "Go to the bedroom via the corridor." Navigation experiments were performed using speech instructions with a waypoint to demonstrate the performance improvement of the SpCoTMHP over the baseline hierarchical path planning method with heuristic path costs (HPP-I) in terms of the weighted success rate at which the robot reaches the closest target (0.590) and passes the correct waypoints. The computation time was significantly improved by 7.14 s with the SpCoTMHP than the baseline HPP-I in advanced tasks. Thus, hierarchical spatial representations provide mutually understandable instruction forms for both humans and robots, thus enabling language-based navigation.

En bloc resection and reconstruction using a talar prosthesis for malignant talar bone tumor: a surgical technique.

En bloc resection is required for treatment of intermediate-grade talar tumors with extraosseous extension (Enneking stage 3) and malignant talar tumors without intra-articular invasion (Enneking stages IA and IIA). After resection, reconstruction options include tibiocalcaneal fusion, frozen autograft, and talar prosthesis; however, a talar prosthesis is preferable because it preserves ankle range of motion, does not cause leg length discrepancy, and is associated with good long-term outcomes. To the best of our knowledge, en bloc resection and reconstruction of a malignant talar tumor has not been previously reported in detail. We report a detailed surgical technique for en bloc resection of a malignant talar bone tumor using combined anterior and lateral approaches followed by reconstruction using a talar prosthesis.

Hippocampal formation-inspired global self-localization: quick recovery from the kidnapped robot problem from an egocentric perspective.

It remains difficult for mobile robots to continue accurate self-localization when they are suddenly teleported to a location that is different from their beliefs during navigation. Incorporating insights from neuroscience into developing a spatial cognition model for mobile robots may make it possible to acquire the ability to respond appropriately to changing situations, similar to living organisms. Recent neuroscience research has shown that during teleportation in rat navigation, neural populations of place cells in the cornu ammonis-3 region of the hippocampus, which are sparse representations of each other, switch discretely. In this study, we construct a spatial cognition model using brain reference architecture-driven development, a method for developing brain-inspired software that is functionally and structurally consistent with the brain. The spatial cognition model was realized by integrating the recurrent state-space model, a world model, with Monte Carlo localization to infer allocentric self-positions within the framework of neuro-symbol emergence in the robotics toolkit. The spatial cognition model, which models the cornu ammonis-1 and -3 regions with each latent variable, demonstrated improved self-localization performance of mobile robots during teleportation in a simulation environment. Moreover, it was confirmed that sparse neural activity could be obtained for the latent variables corresponding to cornu ammonis-3. These results suggest that spatial cognition models incorporating neuroscience insights can contribute to improving the self-localization technology for mobile robots. The project website is https://nakashimatakeshi.github.io/HF-IGL/.

Treatment of Symptomatic Os Supranaviculare in Athletes.

BACKGROUND: Although the incidence of os supranaviculare (OSSN) is generally low, symptomatic OSSN affects athletes. The aim of this study was to assess the variations of OSSN and the results of osteosynthesis between the OSSN and the navicular bone. METHODS: Eleven feet of 10 elite athletes with symptomatic OSSN were treated. There were 3 male and 7 female patients with an average age of 19 years. Eight feet exhibited navicular stress fracture (NSF). Operative treatment was performed in 9 feet of 8 patients and 2 conservatively. Seven OSSNs were fixed with 1 or 2 screw(s) according to their size, using an autologous bone graft. The accompanying NSF was also treated surgically in 4 feet. Foot condition was evaluated using the Japanese Society for Surgery of the Foot (JSSF) midfoot rating scale and sports activity score of the Self-Administered Foot Evaluation Questionnaire (SAFE-Q). RESULTS: The median OSSN was 12.7 mm in width, 5.6 mm in length, and 6.6 mm in height. The dorsal surface of the OSSN required at least 70 mm2 to be fixed using 2 screws. Seven OSSNs of 6 patients treated surgically successfully fused with the navicular. Two small OSSNs that were not stabilized with screws also fused after surgical treatment for NSF. However, one of the 2 OSSNs with NSF treated nonoperatively did not achieve fusion. The patients were followed up for 24-161 months. The median JSSF score improved from 87 to 97.7 postoperatively (P = .00312). The median postoperative SAFE-Q sports score was 84.8. All patients returned to their original activities. CONCLUSION: Our results suggest that osteosynthesis with autologous bone graft was effective for symptomatic OSSNs. Even when the OSSN was small and not suitable for internal fixation, treatment of NSF was effective for union of OSSNs. The OSSN possibly belongs to a part or subtype of NSF.

Anterior Ankle Impingement Syndrome With Spur Fragmentation: Is It an Os Talotibiale?

Background: Bone fragments are often found in ankles with anterior bony impingement. However, whether they are detached osteophytes or accessory bones remains unknown. Methods: Among the 66 continuously enrolled cases of ankles with anterior bony impingement, 32 had a fragment located at the anterior margin of the tibia. The cases of posterior impingement, lateral instability, osteochondral lesions, or free bodies simultaneously treated were excluded. The enrolled subjects were classified into 2 groups: ankles without (group A) and with remarkable spurs (group B). The patients' backgrounds, location of the fragments, clinical scores, and other parameters required to resume sports were compared. The Japanese Society for Surgery of the Foot (JSSF) ankle rating scale was used to evaluate preoperative and postoperative ankle conditions, and the Self-Administered Foot Evaluation Questionnaire (SAFE-Q) was used to evaluate postoperative sports abilities. Results: Eight (seven subjects) and 11 ankles were classified into groups A and B, respectively, and the mean age of the 18 patients was 25.4 (range, 16-37) years. No statistical differences in patient backgrounds or fragment sizes between the groups existed. In group A, the fragments were located on the lateral plateau in 7 of the 8 ankles, whereas in group B, their locations varied. The patients were followed up for a median of 48 months (range, 24-168). No complications were observed. The postoperative JSSF and SAFE-Q sports activity scores were significantly higher in group A than in group B (P <.01 and <.001, respectively). The postoperative term to return to their original sports activities was significantly shorter in group A (P < .05). Conclusion: Anterior bony fragments of the ankle without a remarkable spur were located at a specific site, and the results of arthroscopic treatment were better than in those with remarkable spurs. Such a fragment may be called an os talotibiale. Level of Evidence: Level III, retrospective cohort study.

Metropolis-Hastings algorithm in joint-attention naming game: experimental semiotics study.

We explore the emergence of symbols during interactions between individuals through an experimental semiotic study. Previous studies have investigated how humans organize symbol systems through communication using artificially designed subjective experiments. In this study, we focused on a joint-attention-naming game (JA-NG) in which participants independently categorized objects and assigned names while assuming their joint attention. In the Metropolis-Hastings naming game (MHNG) theory, listeners accept provided names according to the acceptance probability computed using the Metropolis-Hastings (MH) algorithm. The MHNG theory suggests that symbols emerge as an approximate decentralized Bayesian inference of signs, which is represented as a shared prior variable if the conditions of the MHNG are satisfied. This study examines whether human participants exhibit behavior consistent with the MHNG theory when playing the JA-NG. By comparing human acceptance decisions of a partner's naming with acceptance probabilities computed in the MHNG, we tested whether human behavior is consistent with the MHNG theory. The main contributions of this study are twofold. First, we reject the null hypothesis that humans make acceptance judgments with a constant probability, regardless of the acceptance probability calculated by the MH algorithm. The results of this study show that the model with acceptance probability computed by the MH algorithm predicts human behavior significantly better than the model with a constant probability of acceptance. Second, the MH-based model predicted human acceptance/rejection behavior more accurately than four other models (i.e., Constant, Numerator, Subtraction, Binary). Among the models compared, the model using the MH algorithm, which is the only model with the mathematical support of decentralized Bayesian inference, predicted human behavior most accurately, suggesting that symbol emergence in the JA-NG can be explained by the MHNG.

Total Talar Replacement: Surgical Technique.

Background: Total talar replacement is a salvage procedure for end-stage osteonecrosis of the talus. A customized total talar implant is designed with use of computed tomography scans of the healthy opposite side and made of alumina ceramic. The use of such an implant is potentially recommended, with a guarded prognosis, for the treatment of traumatic, steroidal, alcoholic, systemic lupus erythematous, hemophilic, and idiopathic pathologies. The talus is surrounded by the tibia, fibula, calcaneus, and navicular bones, which account for a large portion of the articular surface area. Yoshinaga9 reported that alumina ceramic prostheses were superior in terms of congruency and durability of articular cartilage compared with 316L stainless steel in an in vivo test in dogs. Therefore, alumina ceramic is an ideal material for replacement of the talus to preserve postoperative hindfoot mobility. Description: Total talar replacement is performed with the patient in a supine position. The anterior ankle approach is utilized to exteriorize the talus, facilitating dissection of the ligaments and joint capsule attached to talus. The first osteotomy is performed around the talar neck, perpendicular to the plantar surface of the foot. The talar head fragment is then removed. Subsequent talar osteotomies are performed parallel to the first cutting line, at approximately 2-cm intervals. The attaching articular capsule and ligaments are dissected in each step. The removal of the posterior talar bone fragments is succeeded by careful dissection of the ligament and joint capsule under the periosteum. After dissecting the remaining interosseous talocalcaneal ligament, the foot is distally retracted and a customized talar implant is inserted. After testing and confirming the stability and mobility of the implant, the wound is irrigated with use of normal saline solution. A suction drain is placed anterior to the implant, and the skin is closed after repairing the extensor retinaculum. Alternatives: In cases with a limited area of necrosis, symptoms may improve with a patellar tendon-bearing brace. However, in many cases of symptomatic osteonecrosis of the talus, nonoperative treatment is not expected to improve symptoms. Alternative surgical procedures include ankle arthrodesis and hindfoot arthrodesis, but there are risks of nonunion, leg-length discrepancy as a result of extensive bone loss, and functional decline because of loss of hindfoot motion. Rationale: Total talar replacement is a fundamentally unique treatment concept in which the entire talus is replaced with an artificial implant. Compared with ankle or hindfoot arthrodesis, this procedure preserves the range of motion of the foot and allows for earlier functional recovery. Postoperative results were satisfactory in the subjective evaluation, with no failure requiring revision. This procedure reduces the risk of postoperative failure in patients who are elderly and/or have underlying diseases, who often require a long recovery time. As the talus is a small bone with uniquely vulnerable vascularity, treatment of talar pathology is usually difficult; however, total talar replacement is a potential treatment option for patients with end-stage osteonecrosis of the talus without obesity. Expected Outcomes: The greatest advantage of total talar replacement is the preservation of ankle and hindfoot mobility. Second, a customized talar prosthesis based on a mirrored model of the contralateral, unaffected talus will allow the smooth transfer of body weight from the lower leg to the heel and forefoot-a requirement for a stable gait. Third, the artificial talar prosthesis has a potential advantage in that it minimizes leg-length discrepancy, preventing daily inconvenience for the patient. Twenty years after the development of the implant, replacement with a total talar prosthesis resulted in a median score of 97 out of 100 on the Japanese Society for Surgery of the Foot (JSSF) Ankle-Hindfoot Scale as an objective evaluation and yielded a significant improvement in the subjective evaluation of the Ankle Osteoarthritis Scale (AOS) in a follow-up study over 10 years. The median ankle joint range of motion was 45°, and complications requiring implant replacement never occurred. Important Tips: The skin incision should be placed at the center of the inferior tibial articular surface and curved medially to avoid the medial branch of the superficial peroneal nerve.During the resection of the talus, the attaching ligament and joint capsule are recommended to be debrided prior to osteotomy.Bone fragments should be removed as an entire block in order to avoid leaving small fragments.When inserting the artificial talus, pull the entire foot distally by grasping the heel in order to avoid excessive plantar flexion.During wound closure, the extensor retinaculum should be repaired to avoid skin bowstringing.Although favorable long-term results have been reported, postoperative outcomes in patients with high body mass index have not been adequately investigated. This procedure should be carefully selected on the basis of the physical characteristics of the patient. Acronyms and Abbreviations: AVN = avascular necrosis (osteonecrosis)SLE = systemic lupus erythematousCAD = computer-aided designCT = computed tomographyJSSF = Japanese Society for Surgery of the FootIQR = interquartile rangeAOS = Ankle Osteoarthritis ScalePWB = partial weight-bearingW = weeks.

Emergent communication of multimodal deep generative models based on Metropolis-Hastings naming game.

Deep generative models (DGM) are increasingly employed in emergent communication systems. However, their application in multimodal data contexts is limited. This study proposes a novel model that combines multimodal DGM with the Metropolis-Hastings (MH) naming game, enabling two agents to focus jointly on a shared subject and develop common vocabularies. The model proves that it can handle multimodal data, even in cases of missing modalities. Integrating the MH naming game with multimodal variational autoencoders (VAE) allows agents to form perceptual categories and exchange signs within multimodal contexts. Moreover, fine-tuning the weight ratio to favor a modality that the model could learn and categorize more readily improved communication. Our evaluation of three multimodal approaches - mixture-of-experts (MoE), product-of-experts (PoE), and mixture-of-product-of-experts (MoPoE)-suggests an impact on the creation of latent spaces, the internal representations of agents. Our results from experiments with the MNIST + SVHN and Multimodal165 datasets indicate that combining the Gaussian mixture model (GMM), PoE multimodal VAE, and MH naming game substantially improved information sharing, knowledge formation, and data reconstruction.