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Deep Learning in Random Neural Fields: Numerical Experiments via Neural Tangent Kernel [article]

Kaito Watanabe, Kotaro Sakamoto, Ryo Karakida, Sho Sonoda, Shun-ichi Amari
2022 arXiv   pre-print
A biological neural network in the cortex forms a neural field. Neurons in the field have their own receptive fields, and connection weights between two neurons are random but highly correlated when they are in close proximity in receptive fields. In this paper, we investigate such neural fields in a multilayer architecture to investigate the supervised learning of the fields. We empirically compare the performances of our field model with those of randomly connected deep networks. The behavior
more » ... of a randomly connected network is investigated on the basis of the key idea of the neural tangent kernel regime, a recent development in the machine learning theory of over-parameterized networks; for most randomly connected neural networks, it is shown that global minima always exist in their small neighborhoods. We numerically show that this claim also holds for our neural fields. In more detail, our model has two structures: i) each neuron in a field has a continuously distributed receptive field, and ii) the initial connection weights are random but not independent, having correlations when the positions of neurons are close in each layer. We show that such a multilayer neural field is more robust than conventional models when input patterns are deformed by noise disturbances. Moreover, its generalization ability can be slightly superior to that of conventional models.
arXiv:2202.05254v1 fatcat:asmt4qtl4ncblnht4ud5anmkmy

Treatment to the spastic hands in cerebral palsy

Tomitaro Akiyama, Kotaro Imamura, Yukiyoshi Kawaguchi, Kazumasa Yamaguchi, Zenji Sakamoto
1989 Orthopedics & Traumatology  
doi:10.5035/nishiseisai.37.1478 fatcat:6jjfou5o2ffsbepmwyj33jd7pu

Finding Continuity and Discontinuity in Fish Schools via Integrated Information Theory [article]

Takayuki Niizato, Kotaro Sakamoto, Yoh-ichi Mototake, Takenori Tomaru, Tomotaro Hoshika, Toshiki Fukushima
2018 arXiv   pre-print
Collective behaviour is known to be the result of diverse dynamics and is sometimes likened to a living system. Although many studies have revealed the dynamics of various collective behaviours, their main focus was on the information process inside the collective, not on the whole system itself. For example, the qualitative difference between two elements and three elements as a system has rarely been investigated. Tononi et al. have proposed Integrated Information Theory (IIT) to measure the
more » ... egree of consciousness Φ. IIT postulates that the amount of information loss caused by certain partitions is equivalent to the degree of information integration in the system. This measure is not only useful for estimating the degree of consciousness but can also be applied to more general network systems. Here we applied IIT (in particular, IIT 3.0 using PyPhi) to analyse real fish schools ( Plecoglossus altivelis). Our hypothesis in this study is a very simple one: a living system evolves to raise its Φ value. If we accept this hypothesis, IIT reveals the existence of continuous and discontinuous properties as group size varies. For example, leadership in the fish school emerged for a school size of four or above; but not below three. Furthermore, this transition was not observed by measuring mutual information or in a simple Boids model. This result suggests that integrated information Φ can reveal some inherent properties which cannot be observed using other measures. We also discuss how the fish recognition of the figure-ground relation, that is, what determines the relevant ON and OFF states, may reveal various optimal paths for obtaining the functional evolution of collective behaviour.
arXiv:1812.00718v1 fatcat:pzx2hlwpfvhubeel3amoiuottu

Clinical Significance of Serum and Urinary β2-microglobulin

Masayuki TAKASUGI, Tatsuya HIROTA, Osamu HASEGAWA, Kotaro KIMURA, Shigeru SAKAMOTO, Hiroshi IBAYASHI
1977 RADIOISOTOPES  
doi:10.3769/radioisotopes.26.9_640 fatcat:572mh7m2szho3cxysi4lslqzfy

Helium irradiation effects on deuterium retention in tungsten

Yuki Sakoi, Mitsutaka Miyamoto, Kotaro Ono, Mizuki Sakamoto
2013 Journal of Nuclear Materials  
To investigate effects of helium irradiation on deuterium retention properties in tungsten, thermal desorption spectroscopy of deuterium from a specimen irradiated with a sequential irradiation of 3 keV helium and 1.5 keV deuterium ions at room temperature was measured and the related microstructure was observed by transmission electron microscopy. It was found that pre-irradiation of 3 keV He + ions to fluences of 1.0×10 21 -1.0×10 22 He + /m 2 increased, while the retention of deuterium
more » ... cally decreased above the fluences of 1.0×10 23 He + /m 2 . A similar reduction of deuterium retention was also observed by the pre-exposure of the specimen to a very low energy (~10 eV) and high fluence helium plasma. The reduction effects on deuterium retention are discussed in terms of the formation of linked or interconnected structure of bubbles, which could create an easy release and diffusion path for deuterium desorption.
doi:10.1016/j.jnucmat.2012.10.003 fatcat:bhfpavgg5rhetdteximetaaoi4

Transient SH Wave Propagation of Elastic Plate

Kotaro Miura, Makoto Sakamoto, Yuji Tanabe, F. Gálvez Díaz-Rubio, D.A. Cendón Franco
2021 EPJ Web of Conferences  
We consider the transient wave propagation problem of linear, isotropic and elastic plate applied SH impact loading on the surface. Analytical solution of half-space obtained by the inverse Fourier-Laplace double transform using Cagniard-De Hoop method. The wave propagation problem of plate was considered by using a half-space exact solution and reflect wave from the boundary of plate are expressed using the image method. Some numerical results of stress and displacement components are
more » ... . The mathematical technique appear in the basic problem can apply to the transient P wave propagation and more advanced problems.
doi:10.1051/epjconf/202125002010 fatcat:ccsqoutmbvgbzhllyy2f73nhya

Effect of Functional Water on the Antioxidant Property of Concentrated Reconstituted Juice

Tongjiao Wu, Mitsuki Sakamoto, Natsuki Inoue, Kotaro Imahigashi, Yoshinori Kamitani
2022 Foods  
People often consume juice to easily ingest antioxidants, which can scavenge free radicals and reduce the risk of lifestyle-related diseases. In this study, the SOD assay kit-WST method was used to evaluate the antioxidant activity of two types of functional water, alkaline electrolyzed water (AlEW) and tourmaline water (TMW), reconstituted commercially available (Tropicana) and freshly squeezed concentrated juices and the effect of functional waters on physicochemical parameters and sensory
more » ... luation of reconstituted juices was also analyzed. The reconstituted juice exhibited the highest antioxidant activity when the electrolysis current of AlEW was 8A or the tourmaline stone treatment temperature of TMW was 75 °C. Compared with the control group (69.4%), SOD activity of the reconstituted orange juice in the 8A-AlEW (77.2%) and 75 °C-TMW (84.5%) groups increased by 7.8 and 15.1%, respectively. Furthermore, the color and pH of the functional water reconstituted juice were not significantly different from the juice before concentration, and the taste was better. In summary, functional water could enhance the antioxidant activity of concentrated juice as a formula which could provide novel ideas for the development of functional beverages with antioxidant properties.
doi:10.3390/foods11162531 pmid:36010530 pmcid:PMC9407226 fatcat:ltztp2nejvgnpfet6wzhctoliy

Four-Types of IIT-Induced Group Integrity of Plecoglossus altivelis

Takayuki Niizato, Kotaro Sakamoto, Yoh-ichi Mototake, Hisashi Murakami, Takenori Tomaru, Tomotaro Hoshika, Toshiki Fukushima
2020 Entropy  
Integrated information theory (IIT) was initially proposed to describe human consciousness in terms of intrinsic-causal brain network structures. Particularly, IIT 3.0 targets the system's cause–effect structure from spatio-temporal grain and reveals the system's irreducibility. In a previous study, we tried to apply IIT 3.0 to an actual collective behaviour in Plecoglossus altivelis. We found that IIT 3.0 exhibits qualitative discontinuity between three and four schools of fish in terms of Φ
more » ... lue distributions. Other measures did not show similar characteristics. In this study, we followed up on our previous findings and introduced two new factors. First, we defined the global parameter settings to determine a different kind of group integrity. Second, we set several timescales (from Δ t = 5 / 120 to Δ t = 120 / 120 s). The results showed that we succeeded in classifying fish schools according to their group sizes and the degree of group integrity around the reaction time scale of the fish, despite the small group sizes. Compared with the short time scale, the interaction heterogeneity observed in the long time scale seems to diminish. Finally, we discuss one of the longstanding paradoxes in collective behaviour, known as the heap paradox, for which two tentative answers could be provided through our IIT 3.0 analysis.
doi:10.3390/e22070726 pmid:33286497 pmcid:PMC7517268 fatcat:ds7ozysqqbcszm7h6mzfqrdw5a

One-Step Holographic Photoalignment for Twisted Nematic Liquid Crystal Gratings [chapter]

Kotaro Kawai, Moritsugu Sakamoto, Kohei Noda, Tomoyuki Sasaki, Nobuhiro Kawatsuki, Hiroshi Ono
2017 Holographic Materials and Optical Systems  
Liquid crystal gratings, in which liquid crystal molecules are periodically aligned, are fabricated by highly efficient and practical one-step holographic photoalignment method using a photocrosslinkable polymer liquid crystal (PCLC). This method is an innovative fabrication technique for liquid crystal grating containing a twisted nematic alignment, which does not require a conventional complex fabrication process. In this chapter, three types of liquid crystal gratings with twisted nematic
more » ... gnment are fabricated. Periodic director distributions of these liquid crystal gratings are analyzed based on the elastic continuum theory and observed experimentally using a polarized light optical microscope. Furthermore, the polarization diffraction properties were measured by illumination with a visible laser beam. The resultant liquid crystal gratings exhibit various polarization diffraction properties depending on the director distributions and the polarization states of the incident beams. These polarization diffraction properties are well explained by theoretical analysis based on Jones calculus. These resultant liquid crystal gratings exhibit great potential for application as a diffractive optical element that can simultaneously control the various parameters of the light wave, such as amplitude, polarization states, and propagation direction.
doi:10.5772/67293 fatcat:bkuxvrwetngddexchh2xfd2s3u

Sound recordings of Apis cerana japonica colonies over 24 h reveal unique daily hissing patterns

Satoshi Kawakita, Kotaro Ichikawa, Fumio Sakamoto, Kazuyuki Moriya
2019 Apidologie  
The simultaneous wing movement by multiple worker bees in a colony produces a hissing sound, which is a novel acoustic and vibrational signal of the honey bees. Hissing of honey bees is thought to be a response to direct, threatening stimuli. However, we discovered Japanese honey bees (Apis cerana japonica ) can hiss even without obvious disturbances in previous study. In this study, to understand the temporal characteristics of honey bee hissing, we conducted 24-h sound recordings over 7
more » ... in 2015 and investigated when A. cerana japonica hissed every day. Additionally, we also investigated the relationship of hissing onset and offset times with sunrise and sunset times, and environmental factors. We found that honey bees hiss daily during daytime and most frequently at dawn, with hissing onset/offset occurring mostly within 30 min of sunrise/sunset time. Hissing onset and offset were significantly related to sunrise and sunset times, respectively, and also to solar radiation intensity. The findings reveal that A. cerana japonica hissing has unique temporal patterns, and also shed a new light on vibrational collective behavior in honey bees. acoustic/vibrational behavior / Apis cerana japonica / hissing / honey bees / shimmering
doi:10.1007/s13592-018-0631-x fatcat:czp7hqeyubhbxdoq26o6nljmf4

A Clinicopathologic Study of Breast Cancer Patients during Pregnancy

Kotaro Iijima, Masataka Yoshimoto, Jun Horiguchi, Tetsunari Oyama, Yasuo Morishita, Fujio Kasumi, Goi Sakamoto
2006 The Kitakanto Medical Journal  
& Aims: The purpose of this study was to investigate the influence of pregnancy on breast cancer prognosis by analyzing clinical and pathological features of young patients with breast cancer in relation to last birth. M ethod: A total of 622 y oung breast cancer patients under 35 y ears of age undergoing surgical treatment between 1960 and 1990 at Cancer Institute Hospital were included in this study. The patients were classified into four groups; group A patients who were diagnosed during
more » ... nancy or within one year after delivery,group B patients who were diagnosed from one to three y ears after delivery , group C patients who were diagnosed three years or more after delivery , and group D patients who were nulliparous. All four groups were examined from the viewpoint of clinical and pathological findings with regard to age, disease duration, first childbirth, clinical stage, histopathological ty pe, ly mph node metastasis, and survival. Furthermore, nuclear grade and immunohistochemical staining of both estrogen receptor (ER) and factor-VIII were examined in early-stage breast cancer patients. Result : The incidence of early-stage(0,I and II) breast cancer was significantly(p< 0.05) lower in group A (69%) than in groups C (88%) and D (85%). The incidence of nodal involvement decreased from group A (61%), B (59%), C (51%) to D (43%) in that order. The incidence of nodal involvement in group D was significantly (p<0.05) lower than that in groups A and B. The positive rate of estrogen receptor increased from group A (50%), B (56%) to C (72%) in that order. Disease-free survival was significantly (p<0.05) more favorable in group D than in groups A and C. The similar result was obtained in patients with clinically early-stage breast cancer. Conclusion : Patients who developed breast cancer during pregnancy or within less than one year postpartum have a poor prognosis among patients under 35 years old. Patients having no childbirth history generally have a high risk factor of developing breast cancer,however,breast cancer patients without childbirth history under 35 y ears old result in a favourable prognosis.
doi:10.2974/kmj.56.93 fatcat:ei3x5fepvvewva7yoaf6ot3khm

Autonomous Coordination Technology through Community Organization for Resource Utilization

Titichaya THANAMITSOMBOON, Kotaro HAMA, Riyako SAKAMOTO, Xiaodong LU, Kinji MORI
2011 IEICE transactions on information and systems  
The challenge in resource utilization under dynamic environment is how to utilize appropriate resources to the right users at the right time and the right location. In conventional system, centralized management system is applied but it tends to congest when user requests increase or resources rapidly move. Therefore, this paper proposes Autonomous Coordination Technology (ACT) through community organization for resource utilization. In ACT, a node which has surplus resources autonomously
more » ... ucts community with a surplus-level based size and distributes resources to members which are deficient in resources. ACT consists of autonomous coordination within community and among communities. According to community organization, online property and flexibility can be satisfied. However, it is difficult to achieve service provision timeliness and resource allocation operatability in the mean time. Thus, ACT includes successive transportation method, and autonomous resource allocation which dynamic decision is made by a tradeoff between timeliness and operatability. As a result, the service assurance in terms of timeliness and operatability can be assured. The effectiveness of proposed technology is affirmed through the simulation of taxi dispatching application in terms of response time and standard deviation versus user rates.
doi:10.1587/transinf.e94.d.11 fatcat:epbn7bvqrfghvg6c25kdp774zu

A novel LRP1-binding peptide L57 that crosses the blood brain barrier

Kotaro Sakamoto, Tokuyuki Shinohara, Yusuke Adachi, Taiji Asami, Tetsuya Ohtaki
2017 Biochemistry and Biophysics Reports  
Sakamoto supervised phage display screening and wrote most of this paper. T. Shinohara conducted phage display screening and in situ/ in vivo evaluations. Y.  ... 
doi:10.1016/j.bbrep.2017.07.003 pmid:29090274 pmcid:PMC5645116 fatcat:h2po4psrenfcbe5varjfvwmwqi

Online Spectral Classification for Long-Term Spike Sorting

Kotaro Sakamoto, Keiichi Morikuni, Tetsuya Sakurai, Sumire Matsumoto, Kaspar Vogt
2021 2021 5th International Conference on Medical and Health Informatics  
Declaration of Authorship I, Kotaro SAKAMOTO, declare that this thesis titled, "Online Spectral Classification for Long-Term Spike Sorting" and the work presented in it are my own.  ... 
doi:10.1145/3472813.3472830 fatcat:42iapbo33beobe4c7vnmno6fgy

Crystal Structure of a Human K-Ras G12D Mutant in Complex with GDP and the Cyclic Inhibitory Peptide KRpep-2d

Satoshi Sogabe, Yusuke Kamada, Masanori Miwa, Ayumu Niida, Tomoya Sameshima, Masahiro Kamaura, Kazuko Yonemori, Shigekazu Sasaki, Jun-ichi Sakamoto, Kotaro Sakamoto
2017 ACS Medicinal Chemistry Letters  
The Ras proteins play roles in cell differentiation, proliferation, and survival. Aberrant signaling through Ras-mediated pathways in tumor cells occurs as a result of several types of mutational damage, which most frequently affects the amino acids G12, G13, and Q61. Recently, KRpep-2d was identified as a K-Ras(G12D) selective inhibitory peptide against the G12D mutant of K-Ras, which is a key member of the Ras protein family and an attractive cancer therapeutic target. In this study, the
more » ... al structure of the human K-Ras(G12D) mutant was determined in complex with GDP and KRpep-2d at 1.25 Å resolution. This structure revealed that the peptide binds near Switch II and allosterically blocks protein−protein interactions with the guanine nucleotide exchange factor. This discovery of a unique binding pocket provides valuable information that will facilitate the design of direct Ras inhibitors.
doi:10.1021/acsmedchemlett.7b00128 pmid:28740607 pmcid:PMC5512123 fatcat:6n45flofmjdd7gg6rb65olwsiy
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