350 research outputs found
Material Cost Minimization Problem for Aluminum Alloy Beam using Beam String Structure
Aluminum alloy is a light-weight material with excellent corrosion resistance but low rigidity. When the aluminum alloy is used to a girder bridge, it takes high costs owing to the increment of its stiffness. Therefore in order to reduce a material cost, the cost minimization problem was performed on beam string structure (BSS) made of the aluminum alloy material based on the results of the topology optimization. We focused on the layout of the BSS and diameter of the cable. The conducted simulation made clear the effectivity of the BSS to the aluminum alloy material for a reduction of material cost and increment of the beam span
Vitreoretinal Surgical Robotic System with Autonomous Orbital Manipulation using Vector-Field Inequalities
Vitreoretinal surgery pertains to the treatment of delicate tissues on the
fundus of the eye using thin instruments. Surgeons frequently rotate the eye
during surgery, which is called orbital manipulation, to observe regions around
the fundus without moving the patient. In this paper, we propose the autonomous
orbital manipulation of the eye in robot-assisted vitreoretinal surgery with
our tele-operated surgical system. In a simulation study, we preliminarily
investigated the increase in the manipulability of our system using orbital
manipulation. Furthermore, we demonstrated the feasibility of our method in
experiments with a physical robot and a realistic eye model, showing an
increase in the view-able area of the fundus when compared to a conventional
technique. Source code and minimal example available at
https://github.com/mmmarinho/icra2023_orbitalmanipulation.Comment: 7 pages, 7 figures, accepted on ICRA202
Head-Related Transfer Function Interpolation from Spatially Sparse Measurements Using Autoencoder with Source Position Conditioning
We propose a method of head-related transfer function (HRTF) interpolation
from sparsely measured HRTFs using an autoencoder with source position
conditioning. The proposed method is drawn from an analogy between an HRTF
interpolation method based on regularized linear regression (RLR) and an
autoencoder. Through this analogy, we found the key feature of the RLR-based
method that HRTFs are decomposed into source-position-dependent and
source-position-independent factors. On the basis of this finding, we design
the encoder and decoder so that their weights and biases are generated from
source positions. Furthermore, we introduce an aggregation module that reduces
the dependence of latent variables on source position for obtaining a
source-position-independent representation of each subject. Numerical
experiments show that the proposed method can work well for unseen subjects and
achieve an interpolation performance with only one-eighth measurements
comparable to that of the RLR-based method.Comment: Accepted to International Workshop on Acoustic Signal Enhancement
(IWAENC) 202
Autonomous Coordinated Control of the Light Guide for Positioning in Vitreoretinal Surgery
Vitreoretinal surgery is challenging even for expert surgeons owing to the
delicate target tissues and the diminutive workspace in the retina. In addition
to improved dexterity and accuracy, robot assistance allows for (partial) task
automation. In this work, we propose a strategy to automate the motion of the
light guide with respect to the surgical instrument. This automation allows the
instrument's shadow to always be inside the microscopic view, which is an
important cue for the accurate positioning of the instrument in the retina. We
show simulations and experiments demonstrating that the proposed strategy is
effective in a 700-point grid in the retina of a surgical phantom. Furthermore,
we integrated the proposed strategy with image processing and succeeded in
positioning the surgical instrument's tip in the retina, relying on only the
robot's geometric information and microscopic images.Comment: Accepted on T-MRB 2022, 16 page
Trends in the incidence and mortality of legionellosis in Japan: a nationwide observational study, 1999-2017
This study examined temporal trend, seasonality, and geographical variations of legionellosis incidence and mortality in Japan. This nationwide observational study used the Japanese Vital Statistics and Infectious Diseases Weekly Report (1999-2017) data to calculate legionellosis crude and age-adjusted incidence and mortality rates per 100,000 population by age and sex. Incidence was compared among the 4 seasons and regional incidence among 47 prefectures. Of 13,613 (11,194 men) people with legionellosis in Japan, 725 (569 men) were fatal. Increasing incidence trend occurred from 0.0004 (1999) to 1.37 (2017) per 100,000 population. People aged >= 70 years accounted for 43.1% overall; men's age-adjusted incidence rate was consistently approximately five times higher than for women. Significantly higher incidence occurred in summer than in winter (p=0.013). Geographically, highest incidence (>= 2.0 per 100,000 population) occurred in Hokuriku District, with increasing trends in Hokkaido and middle-part of Japan. Estimated fatality rates decreased consistently at 5.9% (95% confidence interval: - 8.1, - 3.5) annually, from 1999 to 2017, with no trend change point. Increasing legionellosis incidence occurred in Japan during 1999-2017, with declining estimated fatality rates. In this aging society and warming world, disease clinical burden may further deteriorate in future due to increasing incidence trends
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