Waseda University
  • Tokyo, Japan
Recent publications
This study compared lower extremity (LE) muscular strength by 3 groups of female athletes using chronological age and consideration of age of peak height velocity (PHV). Isometric quadriceps, hamstrings, and hip abductors strength were assessed from physically active, pediatric females. The body mass normalized isometric strength (N m/kg) was compared by the 3 age groups. There were 388 young female athletes (<10 years [14.2%], 11-14 years [48.7%], and 15-18 years [37.1%]). The body mass normalized LE strength was lower in 11-14 years compared with <10 years (quadriceps [ P = .001], hamstrings [ P = .001], and hip abductors [ P = .037]) as well as in 15-18 years relative to <10 years in quadriceps ( P = .001) and hamstrings ( P = .001). The analysis results were consistent with both chronological age alone and incorporating effects of age of PHV. In short, body mass normalized LE strength (quadriceps, hamstrings, and hip abductors) of 11-14 years females was lower than <10 years females.
A stereoselective synthesis of C1-C13 segment of poecillastrin C has been achieved. C1-C4 moiety was derived from diallyl tartrate, and the amide group at C3 position was constructed by traceless Staudinger reaction. The C1-C13 segment was submitted to model studies including esterification with bulky alcohol at C1 position and the Stille coupling with vinyl iodide at C13 position. The reactivity of C1 position was affected by the neighboring C2-protective group. When the C2 hydroxy group was protected as TBS ether, the C1 carboxylic acid did not undergo esterification with a bulky secondary alcohol, while the p-methoxybenzylidene N,O-acetal afforded 2,4-dimethyl-3-pentyl ester. The Stille coupling of C1-C13 segment with 1-iodo-1-heptene gave the southern part of poecillastrin C macrolactam attaching with simplified east and west parts.
We aimed to evaluate the blood lactate level in response to two bouts of exercise. First, we hypothesized that blood lactate elevation in response to moderate-intensity aerobic exercise (MIAE) would be lower at the end of the second bout of MIAE than the first bout of MIAE. In this context, we also hypothesized that lactate accumulation at the end of resistance exercise (RE) would be reduced if MIAE is performed before RE ( i.e. , concurrent exercise; CE). If so, we hypothesized that the order of the CE ( i.e. , RE + MIAE vs. MIAE + RE) influences blood lactate kinetics. To test the hypotheses, forty-three healthy men participated in three studies. In study 1, 20 men (age 21 ± 2 years) performed two bouts of a 20-min MIAE separated by a 20-min rest interval. In study 2, 11 men (age 22 ± 1 years) performed RE only and CE (MIAE + RE; AR CE ) with a 20-min rest interval in a crossover design. In study 3, 12 men (age 21 ± 2 years) performed both CEs, which were AR CE and RE + MIAE (RA CE ), with a 20-min rest interval in a crossover design. We measured blood lactate before and at the end of each exercise session. In study 1, the blood lactate response to the second bout of MIAE was lower than that of the first bout ( P < 0.001, r = 0.68). However, the blood lactate response to the AR CE trial was not lower than the response to the RE trial in study 2 ( P = 0.475, r = 0.22). The results of study 3 showed that the RA CE and AR CE trials induced a similar lactate response (MIAE P = 0.423, r = 0.28; RE P = 0.766, d = 0.03). These observations indicate that whereas lactate accumulation might be diminished by a second bout of MIAE, a different type of exercise ( i.e. , aerobic/resistance) did not result in a diminished lactate accumulation in response to a second bout of exercise.
On the ECIR 2023 Virtual Day, I talked about three things: fairness, awareness, and sustainability. This extended abstract summarises the 50-minute talk and provides related resources. Date: 31 March 2023.
Polymer electrolyte is a crucial component of solid‐state‐lithium‐ion batteries that role both as separators and electrolytes. The host polymer and lithium salt selection are crucial for producing a solid polymer electrolyte with optimum characteristics. This research aims to study the effect of lithium acetate (LiCH 3 COO) salt on carboxymethyl cellulose (CMC)‐based solid polymer electrolytes. The LiCH 3 COO‐complexed CMC solid polymer electrolyte was prepared using the solution casting method with various weight percentages of LiCH 3 COO, that is, 0%wt, 10%wt, 20%wt, and 30%wt. The ionic conductivity analysis was conducted by using electrochemical impedance spectroscopy (EIS), infrared analysis by Fourier transform infra‐red (FTIR), mechanical analysis, crystallinity degree analysis with X‐ray diffraction (XRD), and thermogravimetry analysis (TGA), differential thermogravimetry (DTG), and differential scanning calorimetry (DSC). The interaction between Li ⁺ ions and CMC enhanced ionic conductivity, decreased mechanical strength, reduced crystallinity degree, and lowered thermal properties. The CMC/LiCH 3 COO (70/30) SPE was selected as the optimum condition because it exhibited good ionic conductivity and sufficient thermal stability, while it needs a mechanical strength improvement. Molecular dynamics simulations were also performed at the density‐functional tight‐binding (DFTB) level to unravel the molecular mechanism of the Li‐ion hopping in CMC. The CMC/LiCH 3 COO (70/30) showed the highest electrochemical window as high as 3.5 V. Based on the results, CMC complexed with 30 (%wt) LiCH 3 COO salt showed high potential as a polymer electrolyte for lithium‐ion battery applications. Highlights Fabrication of solid polymer electrolyte based on carboxymethyl cellulose complexed with lithium acetate salt was conducted by simple casting solution method. The 30%wt LiCH 3 COO into carboxymethyl cellulose (CMC)‐polymer host showed the highest ionic conductivity of 2.47 × 10 ⁻⁵ S cm ⁻¹ . The 30%wt LiCH 3 COO‐complexed CMC shows some degradation peaks, they are water evaporation, decomplexation, depolymerization, melting, and completely degraded. The density‐functional tight‐binding method suggests that the Li‐ions hop both in perpendicular and parallel directions of the cellulose layers. The CMC/LiCH 3 COO (70/30) showed the highest electrochemical window as high as 3.5 V.
The increasing demand for care of the elderly, coupled with the shortage of caregivers, necessitates the introduction of robotic assistants capable of performing care tasks both intelligently and safely. Central to these tasks, especially those involving tactile interaction, is the ability to make human-in-the-loop adjustments based on individual preferences. In this study, our primary goal was to design and evaluate a system that captures user preferences prior to initiating a tactile care task. Our focus was on range-of-motion training exercises, emphasizing communication that demonstrates motion using the LLM approach. The system combines physical demonstrations with verbal explanations, ensuring adaptability to individual preferences before initiating range-of-motion training. Using the humanoid robot Dry-AIREC, augmented with the linguistic capabilities of ChatGPT, our system was evaluated with 14 young participants. The results showed that the robot could perform the range-of-motion exercises with tactile interactions while simultaneously communicating with the participant. Thus, our proposed system emerges as a promising approach for range-of-motion exercises rooted in human-preference-centered human-robot interaction. Interestingly, although there wasn’t a significant shift in the overall positive subjective impressions when the tuning was performed using ChatGPT, there was an increase in the number of participants who gave the highest rating to the experience.
Traditional rule-based approaches to system monitoring have many areas for improvement. Rules are time-consuming to maintain, and their ability to detect unforeseen future incidents is limited. Online log anomaly detection workflows have the potential to improve upon rule-based methods by providing fine-grained, automated detection of abnormal behavior. However, system and process logs are not static. Code and configuration changes may alter the sequences of log entries produced by these processes, impacting the models trained on their previous behavior. These changes result in false positive signals that can overwhelm production services engineers and drown out alerts for real issues. For this reason, log drift is a significant obstacle to utilizing online log anomaly detection approaches for monitoring in industrial settings. This study explores the different types of log drift and classifies them using a newly introduced taxonomy. It then evaluates the impact these types of drift have on online anomaly detection workflows. Several potential mitigation methods are presented and evaluated based on synthetic and real-world log data. Finally, possible directions for future research are provided and discussed.
We experimentally demonstrated a robust dual-wavelength digital radio-over-fiber (DRoF) link by quasi-2-bit delta-sigma modulated 256- quadrature amplitude modulation orthogonal frequency-division multiplexing (QAM OFDM) data. By optically constructing the 2-bit delta-sigma modulated data with the optical group delay compensation technique, the proposed system combined the advantages from either the conventional 2-bit or 1-bit system. Due to the benefits of higher signal-to-noise ratio and robust anti-nonlinearity to the optical links, the proposed approach performed the widest dynamic ranges of 25.78, 17.81, and 13.46 dB after 25-km single-mode fiber (SMF) transmission by using the 400-MHz 16-, 64-, and 128-QAM OFDM data, respectively. These values were much better comparing with either the conventional 2-bit or 1-bit system. Up to 256-QAM OFDM data with 400-MHz bandwidth was supported by the proposed system for transmitting over 25-km SMF at the lowest overall receiving power of -10.72 dBm. This work provided a good solution for the beyond 5G or 6G DRoF link applications.
A 5G-NR radio over fiber system (RoF) that also incorporates power over fiber (PoF) via a multicore fiber (MCF) link is used to support a reconfigurable metasurface (MSF) antenna for rapid beam steering. Optical signals for RoF-PoF are generated in a central office (CO), and transmitted to the remote antenna unit (RAU) via MCF. A reconfigurable MSF antenna has been designed to perform continuous steering of the radiated beam using indirect optical control of varactor diodes. Subsequently, a proof-of-concept 5G-NR system has been demonstrated for the sub-6 GHz band. The PoF part of the system was able to provide 0 – 5 V to reconfigure the MSF antenna and thus achieve total beam steering of 66°. For the RoF segment, the measured EVM values for 64-QAM scheme vary between 2.6% - 6.9% for all states.
Efficient electromagnetic transient (EMT) simulation is crucial for addressing the challenges associated with the modularity, cascading, and complex topologies of power electronics (PE) systems. This paper introduces a novel portal analysis (PA) approach that adopts a unique “port-component” view, leveraging the characteristics of “ports”. Different from the classic nodal analysis (NA) method, the networks and the components are described based on the portal voltage equations with lower orders. Furthermore, a port tearing method is introduced to partition the circuit, resulting in a block-bordered-diagonal (BBD) matrix and a small number of boundary variables in the extended port equation. The parallel processing of the network solution is implemented by utilizing the BBD forms and the band features. To validate the effectiveness of the proposed PA approach in capturing dynamics, a down-scale dual active bridge (DAB) prototype is constructed. Additionally, a simulated microgrid comprising cascaded H-bridge-type-DAB (CHB-DAB), solar photovoltaic (PV), and energy storage system (ESS) is used to furtherly verify the accuracy and efficiency. The results demonstrate that compared with the NA-based methods, the proposed models exhibit high precision under various transient conditions, with maximum relative errors of less than 2%. Moreover, they achieve a remarkable acceleration of one to two orders of magnitude.
We developed a modality attention motion generation model on the basis of multi-modality prediction. This model provides interpretability about modality usage and demonstrates robustness against disturbances. We used a hierarchical model consisting of low-level recurrent neural networks (RNNs) for processing each modality individually and a high-level RNN that integrates the multi-modality. This integration is achieved by efficiently gating multi-modality and inputting it to the high-level RNN. We verified the interpretability and robustness of the task of inserting a furniture part, which consists of the “approach” phase to bring the wooden dowel closer to the hole and the “insertion” phase. While the proposed model achieves the same task success rate as the conventional model, it clarifies that it refers to vision during “approach” and force during “insertion,” providing interpretability regarding modality use. Furthermore, in contrast to the non-modality attention model, whose task success rate drops significantly under disturbance, the proposed model enhances robustness against disturbances to modalities it does not direct attention during the task, resulting in a consistently high success rate ( $\simeq 90\%$ ).
The purpose of this study was to determine the differences in the growth patterns of the external oblique (EO), internal oblique (IO), and transversus abdominis (TrA) muscles in adolescence baseball players. The subjects were 17 elementary school students (ES), 56 junior high school students (JS), and 21 high school students (HS) who played baseball. The EO, IO, and TrA muscle thicknesses were imaged using an ultrasound imaging device and analyzed separately on the dominant and non-dominant sides. Curve regression estimation of the relationship between EO, IO, and TrA and chronological age was used to read inflection points. An analysis of covariance was also performed, using body weight as a covariate for comparison with each of the EO, IO, and TrA grades. The inflection point readings showed that TrA was 11.26 years old (p<0.01, R²=0.45) for the dominant side and 10.10 years old (p<0.01, R²=0.46) for the non-dominant side, earlier than the inflection points of EO and IO. Analysis of covariance showed no significant difference in EO between any of the grades. IO showed significantly higher values for muscle thickness as the grade increased, both on the dominant and non-dominant side. TrA was higher for JS among ES and JS and higher for HS among ES and HS on both the dominant and non-dominant sides. EO may growth with increasing body size, while IO is interpreted to increase with increasing age due to the movement of baseball. TrA may grow earlier than EO and IO.
The tremendous tidal force that is linked to the supermassive black hole (SMBH) at the center of our galaxy is expected to strongly subdue star formation in its vicinity. Stars within 1'' from the SMBH thus likely formed further from the SMBH and migrated to their current positions. In this study, spectroscopic observations of the star S0-6/S10, one of the closest (projected distance from the SMBH of ≈0''.3) late-type stars were conducted. Using metal absorption lines in the spectra of S0-6, the radial velocity of S0-6 from 2014 to 2021 was measured, and a marginal acceleration was detected, which indicated that S0-6 is close to the SMBH. The S0-6 spectra were employed to determine its stellar parameters including temperature, chemical abundances ([M/H], [Fe/H], [α/Fe], [Ca/Fe], [Mg/Fe], [Ti/Fe]), and age. As suggested by the results of this study, S0-6 is very old (≳10 Gyr) and has an origin different from that of stars born in the central pc region.
The Human Rights Council (HRC) has so far founded more than 50 commissions of inquiry (COIs). While these are mechanisms for fact-finding, their basic aims differ from the fact-finding missions envisioned under traditional international law which have purported to find facts in an impartial and neutral manner to promote peaceful resolution by parties to armed conflict. Most of the COIs are “criminalised” in that they have been mandated to find facts to condemn putative violations, and to identify individuals and entities responsible for those violations, which could help to ensure their prosecution and punishment before international or national criminal proceedings. This is also true for the Commission of Inquiry on Ukraine created in the wake of the Russian Federation’s aggression. At the same time, it declares to use “a victim-centred approach” which, going beyond mere procedural protection of victims, characterises the core methods of fact-finding adopted by the Ukraine COI and the accountability measures it recommends. It has carried out the outstanding number of interviews with victims and requested Ukraine to establish a victim registry as a preliminary step toward a comprehensive reparations program. These victim-oriented aspects suggest a new direction that future fact-finding missions of the HRC may take.
In international law, the special military operation launched by Russia against Ukraine on 24 February 2022 is concerned with the legitimacy and legality of the use of force and the annexation of the Donetsk, Kherson, Luhansk, and Zaporizhzhia regions of Ukraine. The use of force places its legal foundation on the right to self-defence, while annexation in this case corresponds to the acquisition of territory through a treaty. In the case of self-defence, as a legal legitimisation, Russia invokes the ‘Donetsk People’s Republic’ and the ‘Luhansk People’s Republic’s’ request for help on the basis of Treaties on Friendship, Cooperation, and Mutual Assistance, and by incorporating the four regions into Russia, they concluded the treaties on annexation. However, these treaties are invalid based on the regions’ lack of capacity to make such treaties. The regions cannot be recognized as independent states, regardless of their claims for the right to self-determination based on referendums. Furthermore, Russia’s special military operation is considered an illegal use of force in violation of the peremptory norm (jus cogens). All states are obliged to cooperate to bring an end to unlawful situations resulting from the violation of the peremptory norm of non-use of force.
To research the relationship between size of heating range of horizontal furnace and the distribution of incident heat on the surface of beam, 4m and 8m beam-shaped specimens of inorganic material were heated assuming one-hour fire resistance test. The incident heat was greater for the long span(8m) than for the standard span(4m), and more on the sides of the beam than on the bottom. Furthermore, we calculated heat transfer properties based on temperature and incident heat obtained from the experiments. The convective heat transfer coefficient at the beam side was larger for the long span than for the standard span.
The present study focuses on clarifying the composition of the book "UN COUVENT DE LE CORBUSIER" by Le Corbusier in collaboration with Jean Petit. It shows that: 1. 11 types were broadly defined. Furthermore, 108 of the 144 pages could be classified into those types while most of the other 36 pages follow Modulor. 2. In many cases, the basic pattern of the types didn’t use Modulor for the component measurement, but for the margins. 3. This book is positioned as an informative presentation through photographs of priests' and friars' lives and activities in the couvent.
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8,568 members
Christian Dimmer
  • School of International Liberal Studies
Christopher Pokarier
  • School of International Liberal Studies
Keiichi Koyanagi
  • Graduate School of Information, Production and Systems
Jun Tayama
  • Faculty of Human Sciences
Kentaro Kazama
  • Graduate School of Human Sciences
Tokyo, Japan