30 research outputs found

    Eligibility Propagation to Speed up Time Hopping for Reinforcement Learning

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    A mechanism called Eligibility Propagation is proposed to speed up the Time Hopping technique used for faster Reinforcement Learning in simulations. Eligibility Propagation provides for Time Hopping similar abilities to what eligibility traces provide for conventional Reinforcement Learning. It propagates values from one state to all of its temporal predecessors using a state transitions graph. Experiments on a simulated biped crawling robot confirm that Eligibility Propagation accelerates the learning process more than 3 times.Comment: 7 page

    Symmetry Analysis with Spin Crystallographic Groups: Disentangling Spin-Orbit-Free Effects in Emergent Electromagnetism

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    Recent studies identified spin-order-driven phenomena such as spin-charge interconversion without relying on the relativistic spin-orbit interaction. Those physical properties can be prominent in systems containing light magnetic atoms due to sizable exchange splitting and may pave the way for realizations of giant responses correlated with the spin degree of freedom. In this paper, we present a systematic symmetry analysis based on the spin crystallographic groups and identify physical property of a vast number of magnetic materials up to 1500 in total. Absence of spin-orbital entanglement leads to the spin crystallographic symmetry having richer property compared to the well-known magnetic space group symmetry. By decoupling the spin and orbital degrees of freedom, our analysis enables us to take a closer look into the relation between the dimensionality of spin structures and the resultant physical properties and to identify the spin and orbital contributions separately. In stark contrast to the established analysis with magnetic space groups, the spin crystallographic group manifests richer symmetry including spin translation symmetry and leads to nontrivial emergent responses. For representative examples, we discuss geometrical nature of the anomalous Hall effect and magnetoelectric effect, and classify the spin Hall effect arising from the spontaneous spin-charge coupling. Using the power of computational analysis, we apply our symmetry analysis to a wide range of magnets, encompassing complex magnets such as those with noncoplanar spin structures as well as collinear and coplanar magnets. We identify emergent multipoles relevant to physical responses and argue that our method provides a systematic tool for exploring sizable electromagnetic responses driven by spin ordering.Comment: 58 pages, 7 figures, 6 table

    Algorithm for spin symmetry operation search

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    A spin space group provides a suitable way to fully exploit the symmetry of a spin arrangement with a negligible spin-orbit coupling. There has been a growing interest in applying spin symmetry analysis with the spin space group in the field of magnetism. However, there is no established algorithm to search for spin symmetry operations of the spin space group. This paper presents an exhaustive algorithm for determining spin symmetry operations of commensurate spin arrangements. The present algorithm searches for spin symmetry operations from the symmetry operations of a corresponding nonmagnetic crystal structure and determines their spin-rotation parts by solving a Procrustes problem. An implementation is distributed under a permissive free software license in spinspg v0.1.1: https://github.com/spglib/spinspg.Comment: The implementation will be released after publicatio

    A Case of Cervical Epidural Abscess -Diagnosis using MRI and non -surgical treatment -

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    A 65-year-old man with cervical epidural abscess presented with high fever and severe neck pain. On admission, he had difficulty in walking, and the next day paralysis and hyposthesia below the level of C6 developed. Magnetic resonance imaging (MRI) revealed an anterior epidural abscess at C5-7, verteveral bodies levels. All of three blood cultures were positive for Staphylococcus aureus. He was treated with ceftazidame and ampicillin, supplemented with rifampicin and isoniazid for four weeks. The follow-up MRI demonstrated resolution of the abscess and cord compression. After three months, the patient was able to walk with a stick

    In vivo imaging of zebrafish retinal cells using fluorescent coumarin derivatives

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    <p>Abstract</p> <p>Background</p> <p>The zebrafish visual system is a good research model because the zebrafish retina is very similar to that of humans in terms of the morphologies and functions. Studies of the retina have been facilitated by improvements in imaging techniques. <it>In vitro </it>techniques such as immunohistochemistry and <it>in vivo </it>imaging using transgenic zebrafish have been proven useful for visualizing specific subtypes of retinal cells. In contrast, <it>in vivo </it>imaging using organic fluorescent molecules such as fluorescent sphingolipids allows non-invasive staining and visualization of retinal cells <it>en masse</it>. However, these fluorescent molecules also localize to the interstitial fluid and stain whole larvae.</p> <p>Results</p> <p>We screened fluorescent coumarin derivatives that might preferentially stain neuronal cells including retinal cells. We identified four coumarin derivatives that could be used for <it>in vivo </it>imaging of zebrafish retinal cells. The retinas of living zebrafish could be stained by simply immersing larvae in water containing 1 μg/ml of a coumarin derivative for 30 min. By using confocal laser scanning microscopy, the lamination of the zebrafish retina was clearly visualized. Using these coumarin derivatives, we were able to assess the development of the zebrafish retina and the morphological abnormalities induced by genetic or chemical interventions. The coumarin derivatives were also suitable for counter-staining of transgenic zebrafish expressing fluorescent proteins in specific subtypes of retinal cells.</p> <p>Conclusions</p> <p>The coumarin derivatives identified in this study can stain zebrafish retinal cells in a relatively short time and at low concentrations, making them suitable for <it>in vivo </it>imaging of the zebrafish retina. Therefore, they will be useful tools in genetic and chemical screenings using zebrafish to identify genes and chemicals that may have crucial functions in the retina.</p

    歩行時の注視の空間分布における習慣的訪問者と初回訪問者との比較

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    Time manipulation technique for speeding up reinforcement learning in simulations

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    A technique for speeding up reinforcement learning algorithms by using time manipulation is proposed. It is applicable to failure-avoidance control problems running in a computer simulation. Turning the time of the simulation backwards on failure events is shown to speed up the learning by 260% and improve the state space exploration by 12% on the cart-pole balancing task, compared to the conventional Q-learning and Actor-Critic algorithms.Comment: 12 page

    〈他者〉を楽しみ続ける子どもの育成4年次 : 各種カリキュラムの連動を磨き,学校の教育力を高める

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    This practice is based on research conducted at an elementary school affiliated with Hiroshima University. The goal was to nurture children who can continue to enjoy "others.The "others" referred to here is based on the concept of "others" in philosophy. To this end, we spent three years developing a curriculum that would enable students to continue to enjoy "others" in each subject area. Then, in the fourth year, we aimed to link the curriculum in each subject area to enhance the educational capabilities of the school as a whole. There were three major strategies for linking the curriculum. 1. Connecting the curriculum of each subject area with the content of the content. 2. Connecting the curriculum of each subject area with the content of competencies. 3. Connecting the value of learning in each subject area that was practiced discretely by the learners themselves to find their own meaning. This paper is a record of that practice and discussion

    A Proposal of an Input Device Serving as an Unfixed Joystick

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    Ipragliflozin effectively reduced visceral fat in Japanese patients with type 2 diabetes under adequate diet therapy

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    To investigate if ipragliflozin, a novel sodium-glucose co-transporter 2 inhibitor, alters body composition and to identify variables associated with reductions in visceral adipose tissue in Japanese patients with type 2 diabetes mellitus. This prospective observational study enrolled Japanese participants with type 2 diabetes mellitus. Subjects were administered ipragliflozin (50 mg/day) once daily for 16 weeks. Body composition, visceral adipose tissue volume and plasma variables were measured at 0, 8, and 16-weeks. The subjects' lifestyle habits including diet and exercise were evaluated at baseline and 16 weeks. The primary endpoint was defined as the decrease of visceral adipose tissue mass. Twenty-four of 26 enrolled participants completed the study. The visceral adipose tissue decreased significantly (110 ± 33 to 101 ± 36 cm2, p = 0.005) as well as other parameters for metabolic insufficiency including hemoglobin A1c. Seventy-one % of the total body weight reduction (-2.49 kg) was estimated by a decrease in fat mass (-1.77 kg), and the remaining reduction (22%) by water volume (-0.55 kg). A minor but significant reduction in the skeletal muscle index was also observed. Correlation analyses were performed to identify variables associated with changes in visceral adipose tissue and the only significant variable identified was diet therapy (Spearman's r = -0.416, p = 0.043). Ipragliflozin significantly decreased visceral adipose tissue, and improved parametres for metabolic dysfunction. Adequate diet therapy would be necessary to induce and enhance the therapeutic merit
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