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Wyszukujesz frazę "Nishimura, H." wg kryterium: Autor


Tytuł:
Pseudo-orthogonalization of memory patterns for complex-valued and quaternionic associative memories
Autorzy:
Minemoto, T.
Isokawa, T.
Nishimura, H.
Matsui, N.
Tematy:
Hopfield neural network
pseudo-orthogonalization
complex numbers
quaternions
Pokaż więcej
Wydawca:
Społeczna Akademia Nauk w Łodzi. Polskie Towarzystwo Sieci Neuronowych
Powiązania:
https://bibliotekanauki.pl/articles/91608.pdf  Link otwiera się w nowym oknie
Opis:
Hebbian learning rule is well known as a memory storing scheme for associative memory models. This scheme is simple and fast, however, its performance gets decreased when memory patterns are not orthogonal each other. Pseudo-orthogonalization is a decorrelating method for memory patterns which uses XNOR masking between the memory patterns and randomly generated patterns. By a combination of this method and Hebbian learning rule, storage capacity of associative memory concerning non-orthogonal patterns is improved without high computational cost. The memory patterns can also be retrieved based on a simulated annealing method by using an external stimulus pattern. By utilizing complex numbers and quaternions, we can extend the pseudo-orthogonalization for complex-valued and quaternionic Hopfield neural networks. In this paper, the extended pseudo-orthogonalization methods for associative memories based on complex numbers and quaternions are examined from the viewpoint of correlations in memory patterns. We show that the method has stable recall performance on highly correlated memory patterns compared to the conventional real-valued method.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Chaotic states induced by resetting process in Izhikevich neuron model
Autorzy:
Nobukawa, S.
Nishimura, H.
Yamanishi, T.
Liu, J.-Q.
Tematy:
hybrid neuron model
Izhikevich neuron model
chaotic states
Poincar´e section method
Lyapunov method
hybrydowy model neuronowy
model neuronu Izhikevicha
stany chaotyczne
metoda przekroju Poincarego
metoda Lapunowa
Pokaż więcej
Wydawca:
Społeczna Akademia Nauk w Łodzi. Polskie Towarzystwo Sieci Neuronowych
Powiązania:
https://bibliotekanauki.pl/articles/91800.pdf  Link otwiera się w nowym oknie
Opis:
Several hybrid neuron models, which combine continuous spike-generation mechanisms and discontinuous resetting process after spiking, have been proposed as a simple transition scheme for membrane potential between spike and hyperpolarization. As one of the hybrid spiking neuron models, Izhikevich neuron model can reproduce major spike patterns observed in the cerebral cortex only by tuning a few parameters and also exhibit chaotic states in specific conditions. However, there are a few studies concerning the chaotic states over a large range of parameters due to the difficulty of dealing with the state dependent jump on the resetting process in this model. In this study, we examine the dependence of the system behavior on the resetting parameters by using Lyapunov exponent with saltation matrix and Poincar´e section methods, and classify the routes to chaos.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Technical preparations for atmospheric radioactivity monitoring
Autorzy:
Miyamoto, Y.
Oda, T.
Adachi, T.
Noguchi, H.
Nishimura, H.
Usuda, S.
Tematy:
airborne dust
background activity
CTBT
environmental radioactivity
nuclear explosion
radionuclide monitoring
Pokaż więcej
Wydawca:
Instytut Chemii i Techniki Jądrowej
Powiązania:
https://bibliotekanauki.pl/articles/147567.pdf  Link otwiera się w nowym oknie
Opis:
To evaluate the suitability of a location for a radionuclide monitoring station of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) at Takasaki, Japan, the assessment was done in terms of the concentration of natural background radioactive nuclides in airborne dust and soil samples. The samples were taken four times at the proposed site and several points around the site, then their radioactivities were measured by gamma-ray spectrometry. For the airborne dust samples, only natural background radionuclides: 212Pb, 7Be and 214Pb were detected. The radioactivity concentrations of these radionuclides varied in four sampling periods but were almost the same as the previous measurements. For the soil samples, the concentration of an anthropogenic radionuclide, 137Cs, fluctuated among the different sampling points and periods, but the concentration of 40K was constant. These concentrations were 2 to 3 times lower than those of the soil taken at JAERI Tokai. Based on these results, the proposed site was evaluated and has been accepted by the CTBT Organization as a CTBT radionuclide monitoring station.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Complex-valued associative memories with projection and iterative learning rules
Autorzy:
Isokawa, T.
Yamamoto, H.
Nishimura, H.
Yumoto, T.
Kamiura, N.
Matsui, N.
Tematy:
complex-valued neural networks
associative memory
projection
Pokaż więcej
Wydawca:
Społeczna Akademia Nauk w Łodzi. Polskie Towarzystwo Sieci Neuronowych
Powiązania:
https://bibliotekanauki.pl/articles/91682.pdf  Link otwiera się w nowym oknie
Opis:
In this paper, we investigate the stability of patterns embedded as the associative memory distributed on the complex-valued Hopfield neural network, in which the neuron states are encoded by the phase values on a unit circle of complex plane. As learning schemes for embedding patterns onto the network, projection rule and iterative learning rule are formally expanded to the complex-valued case. The retrieval of patterns embedded by iterative learning rule is demonstrated and the stability for embedded patterns is quantitatively investigated.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Novel shape memory actuators
Nowe aktuatory z elementami z pamięcią kształtu
Autorzy:
Tobushi, H.
Miyamoto, K.
Nishimura, Y.
Mitsui, K.
Tematy:
shape memory alloy
shape memory polymer
composite
actuator
two-way
three-way
tape
Pokaż więcej
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Powiązania:
https://bibliotekanauki.pl/articles/279334.pdf  Link otwiera się w nowym oknie
Opis:
In order to develop novel shape memory actuators, the torsional deformation of a shape memory alloy (SMA) tape and the actuator models driven by the tape were investigated. The shape memory composite (SMC) belt composed of SMA tapes and a shape memory polymer (SMP) was fabricated, and the three-way bending characteristics were also investigated. The results obtained can be summarized as follows. In the SMA tape subjected to torsion, the martensitic transformation appears along the edge of the tape due to elongation of the edge of the tape and grows to the central part. The fatigue life in both the pulsating torsion and alternating torsion is expressed by a unified relationship of the dissipated work in each cycle. Based on the two-way motion of an opening and closing door model and a solar-powered active blind model driven by two kinds of SMA tape, it is confirmed that the two-way rotary driving actuator with a small and simple mechanism can be developed by using torsion of the SMA-tape. The SMC belt laminated with the SMP tape and SMA tapes was fabricated. The three-way bending movement of the SMC belt was achieved during heating and cooling based on the charac- teristics of the SMA tapes and the SMP tape. The active SMC actuator with various three-dimentional movements can be developed by applying the three-way properties of the SMC.
W pracy zajęto się aktuatorami nowego typu, w których zastosowano stop z pamięcią kształtu (SMA) w postaci skręcającej się taśmy SMA wywołującej ruch aktuatora. Opracowano kompozytowy pas (SMC) z taśm SMA oraz polimeru wykazującego efekt pamięci kształtu (SMP) oraz zbadano charakterystyki takiego kompozytu przy zginaniu trójosiowym. Rezultaty badań pokazały, że taśma SMA poddana skręcaniu doznaje przemiany martenzytycznej wzdłuż krawędzi z powodu jej wydłużania, która stopniowo przechodzi do środkowej części taśmy. Problem wytrzymałości zmęczeniowej taśmy obciążonej jednokierunkowym i naprzemiennym skręcaniem opisano ujednoliconym wyrażeniem określającym pracę dyssypacji na każdy cykl obciążenia. Zbadano model aktuatora dwustronnego działania do otwierania i zamykania drzwi oraz do sterowania przesłony zasilanej energią słoneczną. Potwierdzono skuteczność torsyjnego aktuatora SMA przy utrzymaniu prostoty konstrukcji takiego mechanizmu. Przeanalizowano przestrzenny ruch kompozytowego pasa SMC indukowanego ogrzewaniem i chłodzeniem w zależności od charakterystyk taśm SMA i SMP. Pokazano, że dzięki właściwościom kompozytu SMC różnych w trzech kierunkach, uzyskanie zdolności ruchowej aktuatora w przestrzeni (3D) jest możliwe.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Directed and elliptic flow observations in Sn+Sn collisions with radioactive beams at 270 MeV/u
Autorzy:
Łukasik, J.
Lynch, W.G.
Sochocka, Anna
Isobe, T.
Brzychczyk, Janusz
Boretzky, K.
Baba, H.
Ikeno, N.
Chiga, N.
Simon, H.
Kim, Y.J.
Fukuda, N.
Atar, L.
Ieki, K.
Lasko, Paweł
Sumikama, T.
Suzuki, D.
Kurata-Nishimura, M.
Nakamura, T.
Nishimura, S.
Jhang, G.
Lee, J.W.
Törnqvist, H.
Kondo, Y.
Lee, H.S.
Otsu, H.
Santamaria, C.
Snoch, A.
Sakurai, H.
Shimizu, Y.
Cerizza, G.
Horvat, A.
Ahn, D.S.
Gasparic, I.
Nakatsuka, N.
Inabe, N.
Kobayashi, T.
Morfouace, P.
Pawłowski, P.
Pelczar, Krzysztof
Sato, H.
Rossi, D.
Togano, Y.
Tangwancharoen, S.
Aumann, T.
Leifels, Y.
Barney, J.
Takeda, H.
Murakami, T.
Yennello, S.J.
Estee, J.
Shane, R.
Kaneko, M.
Wang, R.
Hong, B.
Xiao, Z.G.
Scheit, H.
Tsang, C.Y.
Ono, A.
Manfredi, J.
Tsang, M.B.
McIntosh, A.B.
Zhang, Y.
Suzuki, H.
Opis:
Radioactive tin beams were used to explore the flow observables under varying isospin asymmetries while maintaining a constant total charge. The rapidity dependence of directed flow (v$_{1}$) and elliptic flow (v$_{2}$) was studied for protons, deuterons, tritons, $^{3}$He, and $^{4}$He, produced in neutron-rich $^{132}$Sn + $^{124}$Sn and neutron-deficient $^{108}$Sn + $^{112}$Sn collisions at 270 MeV / nucleon. In general, heavier particles exhibited larger v$_{1}$ and v$_{2}$ values. The experimental data was used to test transport models which simulate heavy ion collisions. Specifically, comparisons were made with Antisymmetrized Molecular Dynamics (AMD) model calculations, which explicitly account for cluster correlations. Two types of momentum-dependent mean field potentials were tested. The results reveal that both v$_{1}$ and v$_{2}$ values are enhanced when the mean field incorporates stronger momentum dependence. In addition, v$_{2}$ exhibits larger sensitivity to symmetry energy than v$_{1}$ but the overall sensitivity to symmetry energy is low. In an attempt to describe the data, different parameter sets have been tried. Most describe either the hydrogen flow or helium flow reasonably well but none describes the flow of all particles simultaneously.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
Constraining nucleon effective masses with flow and stopping observables from the S$\pi$RIT experiment
Autorzy:
Inabe, N.
Leifels, Y.
Shimizu, Y.
Zhang, Y. X.
Chiga, N.
Törnqvist, H.
Lasko, P.
Horvat, A.
Kobayashi, T.
Suzuki, H.
Pawłowski, P.
Sakurai, H.
Sato, H.
Kurata-Nishimura, M.
Kaneko, M.
Santamaria, C.
Scheit, H.
Isobe, T.
Manfredi, J.
Estee, J.
Cerizza, G.
Barney, J.
Pelczar, Krzysztof
Lee, H. S.
Boretzky, K.
Ahn, D. S.
Morfouace, P.
Gasparic, I.
Kondo, Y.
Atar, L.
Lee, J. W.
Lynch, W. G.
Nishimura, S.
Tangwancharoen, S.
Simon, H.
Nakamura, T.
Snoch, A.
Suzuki, D.
Sumikama, T.
Togano, Y.
Wang, R.
Rossi, D.
Yennello, S. J.
Otsu, H.
Kim, Y. J.
Ieki, K.
Zhang, Y.
Takeda, H.
McIntosh, A. B.
Tsang, C. Y.
Aumann, T.
Baba, H.
Brzychczyk, Janusz
Hong, B.
Murakami, T.
Łukasik, J.
Sochocka, Anna
Shane, R.
Xiao, Z. G.
Tsang, M. B.
Nakatsuka, N.
Fukuda, N.
Jhang, G.
Opis:
Properties of the nuclear equation of state (EoS) can be probed by measuring the dynamical properties of nucleus-nucleus collisions. In this study, we present the directed flow (v$_{1}$), elliptic flow (v$_{2}$) and stopping (VarXZ) measured in fixed target Sn + Sn collisions at 270 AMeV with the S$\pi$RIT Time Projection Chamber. We perform Bayesian analyses in which EoS parameters are varied simultaneously within the Improved Quantum Molecular Dynamics-Skyrme (ImQMD-Sky) transport code to obtain a multivariate correlated constraint. The varied parameters include symmetry energy, S$_{0}$, and slope of the symmetry energy, L, at saturation density, isoscalar effective mass, m$^{*}_{s}$/m$_{N}$, and slope of the symmetry energy, L, at saturation density, isoscalar effective mass, m$^{*}_{v}$/m$_{N}$ and the in-medium cross-section enhancement factor η. We find that the flow and VarXZ observables are sensitive to the splitting of proton and neutron effective masses and the in-medium cross-section. Comparisons of ImQMD-Sky predictions to the SπRIT data suggest a narrow range of preferred values for m$^{*}_{s}$/m$_{N}$, m$^{*}_{v}$/m$_{N}$ and η.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
Rapidity distributions of Z = 1 isotopes and the nuclear symmetry energy from Sn+Sn collisions with radioactive beams at 270 MeV/nucleon
Autorzy:
Inabe, N.
Leifels, Y.
Shimizu, Y.
Chiga, N.
Törnqvist, H.
Lasko, P.
Horvat, A.
Kobayashi, T.
Gašparić, I.
Suzuki, H.
Pawłowski, P.
Sakurai, H.
Sato, H.
Xiao, Z.
Kurata-Nishimura, M.
Kaneko, M.
Santamaria, C.
Ono, A.
Scheit, H.
Isobe, T.
Manfredi, J.
Cerizza, G.
Estee, J.
Barney, J.
Yurkon, J.
Ichihara, T.
Lee, H. S.
Boretzky, K.
Ahn, D. S.
Morfouace, P.
Olsen, R.
Kondo, Y.
Atar, L.
Lee, J. W.
Lynch, W. G.
Nishimura, S.
Tangwancharoen, S.
Simon, H.
Nakamura, T.
Suzuki, D.
Sumikama, T.
Togano, Y.
Wang, R.
Rossi, D.
Yennello, S. J.
Otsu, H.
Kim, Y. J.
Ieki, K.
Zhang, Y.
Ikeno, N.
Takeda, H.
Pelczar, K.
McIntosh, A. B.
Tsang, C. Y.
Aumann, T.
Baba, H.
Brzychczyk, Janusz
Hong, B.
Murakami, T.
Łukasik, J.
Shane, R.
Tsang, M. B.
Nakatsuka, N.
Fukuda, N.
Jhang, G.
Opis:
The rapidity distributions of hydrogen isotopes emitted from central collisions of neutron-rich 132Sn+124Sn and neutron-deficient 108Sn+112Sn systems at 270 MeV/nucleon were investigated at RIKEN-RIBF. The data are compared with antisymmetrized molecular dynamics (AMD) calculations and the rapidity distributions can be reproduced after adjusting the in-medium nucleon-nucleon cross sections. The double ratios between the two reaction systems taken for the relative yields of deuteron to proton (d/p) and triton to proton (t/p) are further examined in the midrapidity domain, where the adjustments in the AMD calculations do not affect much on them. The d/p and t/p double ratios at midrapidity agree well with the ratio of the system neutron numbers and its squared value, respectively, and the rapidity dependence of these double ratios is consistent with a picture of partial mixing of colliding nuclei. By comparing with the AMD model which shows a strong symmetry energy dependence of the t/p double ratio, the experimental result in the midrapidity domain favors the calculation with a symmetry-energy slope parameter around L=46 MeV rather than L=108 MeV.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł

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