71 research outputs found

    Virtual Reality approaches for evacuation simulation of various disasters

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    This paper presents a virtual reality (VR) system of evacuation in the cases of various disasters. We considered a combination of disasters under realistic scenarios. Disaster simulations by numerical models were imported into the VR system to express a realistic situation. Not only disaster experts but also designers and non-professionals are able to share realistic experiences for escape from the disasters. This system is useful for performance-based design, planning of escape, disaster prevention, evacuation drill etc. The VR system consists of Building Information Modelling, physical simulation models for disasters and human behaviourā€™s simulation

    Variable Shape Attitude Control Demonstration with Microsat Hibari

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    This paper presents the ongoing feasibility study and bus system for microsatellite ā€œHibariā€. The main technical missions for Hibari is called ā€œVariable Shape Attitude Control (VSAC)ā€. This VSAC is based on an idea to utilize a reaction torque when a part of the satellite structure, for example, solar array paddles is appropriately rotated by actuators. The previous research concluded that VSAC successfully achieved the rapid maneuvering while maintain the high attitude stability against disturbances [1], and thus, it can be applied to a variety of advanced attitude control missions. Hibari project also aims at its application to astronomical mission requiring high pointing stability and agile maneuvering. This paper is mainly comprised of 3 parts: detail mission statement, ongoing feasibility studies and bus system configuration. First, we mention the mission requirement and detail mission sequence for both technical and science missions. Second, we show the ongoing feasibility studies to confirm that all mission requirement is satisfied by VSAC. Third, this paper describes each subsystem configuration to meet the system requirement stated in the missionā€™s section. And then, we wrap up in the conclusion section and stated the future study for advanced VSAC use in the end

    Independent calculation-based verification of volumetric-modulated arc therapyā€“stereotactic body radiotherapy plans for lung cancer

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    This study aimed to investigate the feasibility of independent calculationā€based verification of volumetricā€modulated arc therapy (VMAT)ā€“stereotactic body radiotherapy (SBRT) for patients with lung cancer using a secondary treatment planning system (sTPS). In all, 50 patients with lung cancer who underwent VMATā€SBRT between April 2018 and May 2019 were included in this study. VMATā€SBRT plans were devised using the Collapsedā€Cone Convolution in RayStation (primary TPS: pTPS). DICOM files were transferred to Eclipse software (sTPS), which utilized the Eclipse software, and the dose distribution was then recalculated using Acuros XB. For the verification of dose distribution in homogeneous phantoms, the differences among pTPS, sTPS, and measurements were evaluated using passing rates of a dose difference of 5% (DD5%) and gamma index of 3%/2 mm (Ī³3%/2 mm). The ArcCHECK cylindrical diode array was used for measurements. For independent verification of doseā€volume parameters per the patientā€™s geometry, doseā€volume indices for the planning target volume (PTV) including D95% and the isocenter dose were evaluated. The mean differences (Ā± standard deviations) between the pTPS and sTPS were then calculated. The gamma passing rates of DD5% and Ī³3%/2 mm criteria were 99.2 Ā± 2.4% and 98.6 Ā± 3.2% for pTPS vs. sTPS, 92.9 Ā± 4.0% and 94.1 Ā± 3.3% for pTPS vs. measurement, and 93.0 Ā± 4.4% and 94.3 Ā± 4.1% for sTPS vs. measurement, respectively. The differences between pTPS and sTPS for the PTVs of D95% and the isocenter dose were āˆ’3.1 Ā± 2.0% and āˆ’2.3 Ā± 1.8%, respectively. Our investigation of VMATā€SBRT plans for lung cancer revealed that independent calculationā€based verification is a timeā€efficient method for patientā€specific quality assurance

    Development and Initial On-orbit Performance of Multi-Functional Attitude Sensor using Image Recognition

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    This paper describes a multi-functional attitude sensor mounted on the ā€œInnovative Satellite 1stā€ led by Japan Aerospace Exploration Agency which was launched in January 2019. In order to achieve the high accuracy determination in low cost, we developed a novel attitude sensor utilizing real-time image recognition technology, named ā€œDeep Learning Attitude Sensor (DLAS)ā€. DLAS has two type of attitude sensors: Star Tracker(STT) and Earth Camera (ECAM). For the low-cost development, we adopted commercial off-the-shelf cameras. DLAS uses real-time image recognition technology and a new attitude determination algorithm. In this paper, we present the missions, methods and system configuration of DLAS and initial results of on-orbit experiment that was conducted after the middle of February 2019, and it is confirmed that attitude determinations using ECAM and STT are performed correctly

    Enriched Expression of Serotonin 1B and 2A Receptor Genes in Macaque Visual Cortex and their Bidirectional Modulatory Effects on Neuronal Responses

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    To study the molecular mechanism how cortical areas are specialized in adult primates, we searched for area-specific genes in macaque monkeys and found striking enrichment of serotonin (5-hydroxytryptamine, 5-HT) 1B receptor mRNA, and to a lesser extent, of 5-HT2A receptor mRNA, in the primary visual area (V1). In situ hybridization analyses revealed that both mRNA species were highly concentrated in the geniculorecipient layers IVA and IVC, where they were coexpressed in the same neurons. Monocular inactivation by tetrodotoxin injection resulted in a strong and rapid (<3 h) downregulation of these mRNAs, suggesting the retinal activity dependency of their expression. Consistent with the high expression level in V1, clear modulatory effects of 5-HT1B and 5-HT2A receptor agonists on the responses of V1 neurons were observed in in vivo electrophysiological experiments. The modulatory effect of the 5-HT1B agonist was dependent on the firing rate of the recorded neurons: The effect tended to be facilitative for neurons with a high firing rate, and suppressive for those with a low firing rate. The 5-HT2A agonist showed opposite effects. These results suggest that this serotonergic system controls the visual response in V1 for optimization of information processing toward the incoming visual inputs

    Paraneoplastic Antigen-Like 5 Gene (PNMA5) Is Preferentially Expressed in the Association Areas in a Primate Specific Manner

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    To understand the relationship between the structure and function of primate neocortical areas at a molecular level, we have been screening for genes differentially expressed across macaque neocortical areas by restriction landmark cDNA scanning (RLCS). Here, we report enriched expression of the paraneoplastic antigen-like 5 gene (PNMA5) in association areas but not in primary sensory areas, with the lowest expression level in primary visual cortex. In situ hybridization in the primary sensory areas revealed PNMA5 mRNA expression restricted to layer II. Along the ventral visual pathway, the expression gradually increased in the excitatory neurons from the primary to higher visual areas. This differential expression pattern was very similar to that of retinol-binding protein (RBP) mRNA, another association-area-enriched gene that we reported previously. Additional expression analysis for comparison of other genes in the PNMA gene family, PNMA1, PNMA2, PNMA3, and MOAP1 (PNMA4), showed that they were widely expressed across areas and layers but without the differentiated pattern of PNMA5. In mouse brains, PNMA1 was only faintly expressed and PNMA5 was not detected. Sequence analysis showed divergence of PNMA5 sequences among mammals. These findings suggest that PNMA5 acquired a certain specialized role in the association areas of the neocortex during primate evolution

    Investigation of 4D dose in volumetric modulated arc therapy-based stereotactic body radiation therapy: does fractional dose or number of arcs matter?

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    The aim of this study was to assess the impact of fractional dose and the number of arcs on interplay effects when volumetric modulated arc therapy (VMAT) is used to treat lung tumors with large respiratory motions. A three (fractional dose of 4, 7.5 or 12.5 Gy) by two (number of arcs, one or two) VMAT plan was created for 10 lung cancer cases. The median 3D tumor motion was 17.9 mm (range: 8.2ā€“27.2 mm). Ten phase-specific subplans were generated by calculating the dose on each respiratory phase computed tomography (CT) scan using temporally assigned VMAT arcs. We performed temporal assignment of VMAT arcs using respiratory information obtained from infrared markers placed on the abdomens of the patients during CT simulations. Each phase-specific dose distribution was deformed onto exhale phase CT scans using contour-based deformable image registration, and a 4D plan was created by dose accumulation. The gross tumor volume dose of each 4D plan (4D GTV dose) was compared with the internal target volume dose of the original plan (3D ITV dose). The near-minimum 4D GTV dose (D99%) was higher than the near-minimum 3D internal target volume (ITV) dose, whereas the near-maximum 4D GTV dose (D1%) was lower than the near-maximum 3D ITV dose. However, the difference was negligible, and thus the 4D GTV dose corresponded well with the 3D ITV dose, regardless of the fractional dose and number of arcs. Therefore, interplay effects were negligible in VMAT-based stereotactic body radiation therapy for lung tumors with large respiratory motions
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