120 research outputs found
Clustering Method for Time-Series Images Using Quantum-Inspired Computing Technology
Time-series clustering serves as a powerful data mining technique for
time-series data in the absence of prior knowledge about clusters. A large
amount of time-series data with large size has been acquired and used in
various research fields. Hence, clustering method with low computational cost
is required. Given that a quantum-inspired computing technology, such as a
simulated annealing machine, surpasses conventional computers in terms of fast
and accurately solving combinatorial optimization problems, it holds promise
for accomplishing clustering tasks that are challenging to achieve using
existing methods. This study proposes a novel time-series clustering method
that leverages an annealing machine. The proposed method facilitates an even
classification of time-series data into clusters close to each other while
maintaining robustness against outliers. Moreover, its applicability extends to
time-series images. We compared the proposed method with a standard existing
method for clustering an online distributed dataset. In the existing method,
the distances between each data are calculated based on the Euclidean distance
metric, and the clustering is performed using the k-means++ method. We found
that both methods yielded comparable results. Furthermore, the proposed method
was applied to a flow measurement image dataset containing noticeable noise
with a signal-to-noise ratio of approximately 1. Despite a small signal
variation of approximately 2%, the proposed method effectively classified the
data without any overlap among the clusters. In contrast, the clustering
results by the standard existing method and the conditional image sampling
(CIS) method, a specialized technique for flow measurement data, displayed
overlapping clusters. Consequently, the proposed method provides better results
than the other two methods, demonstrating its potential as a superior
clustering method.Comment: 13 pages, 4 figure
EMG activity during 2000 m rowing
This study aimed to clarify the changes in the activity of the trunk and lower limb muscles during 2000-m rowing. Ten male rowers performed a 2000-m race simulation on a rowing ergometer. Electromyography results of the abdominal muscles, back muscles, gluteus maximus (GMax), biceps femoris (BF), and rectus femoris (RF) were recorded. The electromyographic activity during the three strokes after the start (initial stage), at 1000m (middle stage), and before the end (final stage) were analyzed. From the handle position, the rowing motion was divided into five phases (early-drive, middle-drive, late-drive, early-recovery, and late-recovery). The peak activities of the abdominal muscles, back muscles, GMax, and BF in each stroke of the rowing motion were delayed at the middle and final stages compared to the initial stage (P < 0.05). The peak activity of the RF was observed in the late-drive phase at the initial stage, whereas a high RF activity was observed in the middle-drive phase at the middle and final stages (P < 0.05). Considering the results of the activity of the back muscles and RF, RF muscular endurance enhancement may lead to a decrease in the load on the back muscles and help prevent muscular low back pain in rowers
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Comparison between Integrated Backscatter Intravascular Ultrasound and 64-Slice Multi-Detector Row Computed Tomography for Tissue Characterization and Volumetric Assessment of Coronary Plaques
Background: The purpose of this study was to determine the cut-off values of Hounsfield units (HU) for the discrimination of plaque components and to evaluate the feasibility of measurement of the volume of plaque components using multi-detector row computed tomography (MDCT). Methods: Coronary lesions (125 lesions in 125 patients) were visualized by both integrated backscatter intravascular ultrasound (IB-IVUS) and 64-slice MDCT at the same site. The IB values were used as a gold standard to determine the cut off values of HU for the discrimination of plaque components. Results: Plaques were classified as lipid pool (n =50), fibrosis (n =65) or calcification (n =35) by IB-IVUS. The HU of lipid pool, fibrosis and calcification were 18 ± 18 HU (−19 to 58 HU), 95 ± 24 HU (46 to 154 HU) and 378 ± 99 HU (188 to 605 HU), respectively. Using receiver operating characteristic curve analysis, a threshold of 50 HU was the optimal cutoff values to discriminate lipid pool from fibrosis. Lipid volume measured by MDCT was correlated with that measured by IB-IVUS (r =0.66, p <0.001), whereas fibrous volume was not (r =0.21, p =0.059). Conclusion: Lipid volume measured by MDCT was moderately correlated with that measured by IB-IVUS. MDCT may be useful for volumetric assessment of the lipid volume of coronary plaques, whereas the assessment of fibrosis volume was unstable
Ultrafast Control of Crystal Structure in a Topological Charge-Density-Wave Material
Optical control of crystal structures is a promising route to change physical
properties including topological nature of a targeting material. Time-resolved
X-ray diffraction measurements using the X-ray free-electron laser are
performed to study the ultrafast lattice dynamics of VTe, which shows a
unique charge-density-wave (CDW) ordering coupled to the topological surface
states as a first-order phase transition. A significant oscillation of the CDW
amplitude mode is observed at a superlattice reflection as well as Bragg
reflections. The frequency of the oscillation is independent of the fluence of
the pumping laser, which is prominent to the CDW ordering of the first-order
phase transition. Furthermore, the timescale of the photoinduced
1 to 1 phase transition is independent of the period of
the CDW amplitude mode
Key factors in simulating the equatorial Atlantic zonal sea surface temperature gradient in a coupled general circulation model
Causes of the coupled model bias in simulating the zonal sea surface temperature (SST) gradient in the equatorial Atlantic are examined in three versions of the same coupled general circulation model (CGCM) differing only in the cumulus convection scheme. One version of the CGCM successfully simulates the mean zonal SST gradient of the equatorial Atlantic, in contrast to the failure of the Coupled Model Intercomparison Project phase 3 models. The present analysis shows that key factors to be successful are high skills in simulating the meridional location of the Intertropical Convergence Zone, the precipitation over northern South America, and the southerly winds along the west coast of Africa associated with the West African monsoon in boreal spring. Model biases in the Pacific contribute to the weaker precipitation over northern South America. Uncoupled experiments with the atmospheric component further confirm the importance of remote influences on the development of the equatorial Atlantic bias.
Key Points:
The zonal SST gradient of the equatorial Atlantic is well simulated in a CGCM;
Key factors for the realistic simulation of the Atlantic SST are presented;
Remote forcing from the Pacific may contribute to the Atlantic SST bia
Phase Ib Study of Lenvatinib Plus Pembrolizumab in Patients With Unresectable Hepatocellular Carcinoma
PURPOSE The immunomodulatory effect of lenvatinib (a multikinase inhibitor) on tumor microenvironments may contribute to antitumor activity when combined with programmed death receptor-1 (PD-1) signaling inhibitors in hepatocellular carcinoma (HCC). We report results from a phase Ib study of lenvatinib plus pembrolizumab (an anti-PD-1 antibody) in unresectable HCC (uHCC). PATIENTS AND METHODS In this open-label multicenter study, patients with uHCC received lenvatinib (bodyweight 3 treatment-related adverse events occurred in 67% (grade 5, 3%) of patients. No new safety signals were identified. CONCLUSION Lenvatinib plus pembrolizumab has promising antitumor activity in uHCC. Toxicities were manageable, with no unexpected safety signals
Development of Antiferromagnetic Heusler Alloys for the Replacement of Iridium as a Critically Raw Material
As a platinum group metal, iridium (Ir) is the scarcest element on the earth but it has been widely used as an antiferromagnetic layer in magnetic recording, crucibles and spark plugs due to its high melting point. In magnetic recording, antiferromagnetic layers have been used to pin its neighbouring ferromagnetic layer in a spin-valve read head in a hard disk drive for example. Recently, antiferromagnetic layers have also been found to induce a spin-polarised electrical current. In these devices, the most commonly used antiferromagnet is an Ir-Mn alloy because of its corrosion resistance and the reliable magnetic pinning of adjacent ferromagnetic layers. It is therefore crucial to explore new antiferromagnetic materials without critical raw materials. In this review, recent research on new antiferromagnetic Heusler compounds and their exchange interactions along the plane normal is discussed. These new antiferromagnets are characterised by very sensitive magnetic and electrical measurement techniques recently developed to determine their characteristic temperatures together with atomic structural analysis. Mn-based alloys are found to be most promising based on their robustness against atomic disordering and large pinning strength up to 1.4 kOe, which is comparable with that for Ir-Mn. The search for new antiferromagnetic films and their characterisation are useful for further miniaturisation and development of spintronic devices in a sustainable manner
The Design of Learning Support Environment for Nurturing Academic Writing Skills in Higher Education
本研究ではライティングセンターによる個別チュータリング、eラーニング教材の開発、オンラインチュータリングを実施することで、アカデミック・ライティング力を育むための教育システムの開発とそのデザイン原則の導出を目指した。個別チュータリングに関しては授業連携による利用が約65%を占め、なかでも初年次教育の利用が多く、教員による利用指示の背景にはライティングセンター教職員との意見交換の機会が影響していることを示した。eラーニング教材に関しては、アカデミック・ライティング力を育むための一定の効果が見受けられた。またオンラインチュータリングに関しては、対面と同様であると感じている学生がいる一方で、構成を考える際に図式化することで理解が深まると考える学生もおり、相談内容に応じて対面が望ましい傾向が指摘された。加えて、学生のコミュニケーションスタイルにより対面とオンラインチュータリングに対する心理的距離が異なるため、両方の環境を整備する必要性が示された。平成28年度関西大学教育研究高度化促進費「アカデミック・ライティング力を育むための教育システム開発とデザイン原則の導出」の一部である
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