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Compensation of Cross-Coupling in MIMO Inductive Power Transfer Systems
No full textThis paper proposes a design principle for reactance compensation circuit for multiple-input multiple-output (MIMO) inductive power transfer (IPT) where the primary side employs a coil array to send power to a receiving coil array located at the secondary side. Delivering wireless power over multiple streams, MIMO topology is an effective approach to relax strict burdens on system components in high-power IPT applications. An important requirement in MIMO topology is a method to mitigate cross-coupling inside the coil arrays so that load-independent constant-current and constant-voltage can be realized in the same fashion as conventional single-input single-output IPT. Based on transfer matrix analysis, this paper proposes a design principle indicating that passive compensation circuit should implement the negative of the cross-coupling’s reactance matrix to cancel it in the reactance domain. The proposed design is independent of the transmission distance, applicable to MIMO IPT systems at arbitrary scale and does not require the coil arrays to employ any decoupling structure. Full-wave electromagnetic simulations with 3×2 MIMO and experiments with 2×2 MIMO are provided to verify effectiveness and feasibility of the proposed scheme.journal articl
Is Boundary Annotation Necessary? Evaluating Boundary-Free Approaches to Improve Clinical Named Entity Annotation Efficiency: Case Study
No full textBackground:
Named entity recognition (NER) is a fundamental task in natural language processing. However, it is typically preceded by named entity annotation, which poses several challenges, especially in the clinical domain. For instance, determining entity boundaries is one of the most common sources of disagreements between annotators due to questions such as whether modifiers or peripheral words should be annotated. If unresolved, these can induce inconsistency in the produced corpora, yet, on the other hand, strict guidelines or adjudication sessions can further prolong an already slow and convoluted process.
Objective:
The aim of this study is to address these challenges by evaluating 2 novel annotation methodologies, lenient span and point annotation, aiming to mitigate the difficulty of precisely determining entity boundaries.
Methods:
We evaluate their effects through an annotation case study on a Japanese medical case report data set. We compare annotation time, annotator agreement, and the quality of the produced labeling and assess the impact on the performance of an NER system trained on the annotated corpus.
Results:
We saw significant improvements in the labeling process efficiency, with up to a 25% reduction in overall annotation time and even a 10% improvement in annotator agreement compared to the traditional boundary-strict approach. However, even the best-achieved NER model presented some drop in performance compared to the traditional annotation methodology.
Conclusions:
Our findings demonstrate a balance between annotation speed and model performance. Although disregarding boundary information affects model performance to some extent, this is counterbalanced by significant reductions in the annotator’s workload and notable improvements in the speed of the annotation process. These benefits may prove valuable in various applications, offering an attractive compromise for developers and researchers.journal articl
The status of MRI databases across the world focused on psychiatric and neurological disorders
No full textNeuroimaging databases for neuro-psychiatric disorders enable researchers to implement data-driven research approaches by providing access to rich data that can be used to study disease, build and validate machine learning models, and even redefine disease spectra. The importance of sharing large, multi-center, multi-disorder databases has gradually been recognized in order to truly translate brain imaging knowledge into real-world clinical practice. Here, we review MRI databases that share data globally to serve multiple psychiatric or neurological disorders. We found 42 datasets consisting of 23,293 samples from patients with psychiatry and neurological disorders and healthy controls; 1245 samples from mood disorders (major depressive disorder and bipolar disorder), 2015 samples from developmental disorders (autism spectrum disorder, attention-deficit hyperactivity disorder), 675 samples from schizophrenia, 1194 samples from Parkinson's disease, 5865 samples from dementia (including Alzheimer's disease), We recognize that large, multi-center databases should include governance processes that allow data to be shared across national boundaries. Addressing technical and regulatory issues of existing databases can lead to better design and implementation and improve data access for the research community. The current trend toward the development of shareable MRI databases will contribute to a better understanding of the pathophysiology, diagnosis and assessment, and development of early interventions for neuropsychiatric disorders.journal articl
Phase-Dependent Damping Rate of Josephson Plasmons in the Nonequilibrium Steady State
Get PDFWe calculate the damping rate of Josephson plasmons due to thermally excited quasiparticles in a nonequilibrium steady state. It is known that the experimentally observed dependence of the damping rate on the phase difference behaves in the opposite way to that of the theory. It is shown that this problem can be solved by calculating the damping rate by incorporating changes in the electronic state at the resonant frequency. When the phase difference is large, the broadening of the one-particle state is large due to the presence of a dc current and brings about the effective thermalization, so that the nonequilibrium correction becomes small. Conversely, when the phase difference is small, the nonequilibrium correction becomes large and causes a smaller damping rate due to a reduction in the effective temperature. This dependence of the nonequilibrium correction on the phase difference results in a damping rate that is consistent with experimental results.journal articl
Analysis of self-avoidance mechanisms in the root parasitic plant Phtheirospermum japonicum
Get PDF奈良先端科学技術大学院大学博士(バイオサイエンス)doctoral thesi
AR Avatar-Mediated Approach for Mitigating Social Anxiety during In-person Conversations
Get PDF奈良先端科学技術大学院大学修士(工学)master thesi
Enhancing Photocathodic Performances of Particulate-CuGaS2-Based Photoelectrodes via Conjugation with Conductive Organic Polymers for Efficient Solar-Driven Hydrogen Production and CO2 Reduction
No full textModification with conductive organic polymers consisting of a thiophane- or pyrrole-based backbone improved the cathodic photocurrent of a particulate-CuGaS2-based photoelectrode under simulated solar light. Among these polymers, poly(3,4-ethylenedioxythiophene) (PEDOT) was the most effective in the improvements, providing a photocurrent 670 times as high as that of the bare photocathode. An incident-photon-to-current efficiency (IPCE) for water reduction to form H2 under monochromatic light irradiation (450 nm at 0 V vs RHE) was ca. 11%. The most important point is that modification of the conductive organic polymers does not involve any vacuum processes. This importance lies in the use of an electrochemically oxidative polymerization, not in a physical process such as vapor deposition of metal conductors. This is expected to be advantageous in the large-scale application of photocathodes consisting of particulate photocatalyst materials toward industrial solar-hydrogen production using photoelectrochemical-cell-based devices. Artificial photosynthesis of water splitting and CO2 reduction under simulated solar light was demonstrated by combining the PEDOT-modified CuGaS2 photocathode with a CoOx-loaded BiVO4 photoanode. Furthermore, how the cathodic photocurrent of the particulate-CuGaS2-based photocathode was drastically improved by the modification was clarified based on various characterizations and control experiments as follows: (1) selectively filling cavities between the particulate CuGaS2 photocatalysts and a conductive substrate (FTO; fluorine-doped tin oxide) with the polymers and (2) using a large driving force for carrier transportation governed by the polymers’ redox potentials adjusted by functional groups.journal articl
Intelligent surgical robotics, medical image analysis, and brain imaging researches at Harvard
No full textvideo/mp4講演日: 2024年5月21日講演場所: エーアイ大講義室, AI Inc. Seminar Hall （L1）vide
タイワガタ エーアイ ワ ゲンゴ シャカイ オ カエルカ
No full textvideo/mp4対話型AIはユーザの様々な質問に答えることができ、検索や機械翻訳、自動要約といった既存のアプリケーションを超えた、多様なサービスを実現しています。この講座では、基盤技術について解説し、今後、言語および社会へどのような影響をもたらすのか議論します。講演日: 2024年10月5日講演場所: 生駒市生涯学習施設 たけまるホール（大ホール）講演者所属: 情報科学領域vide
Region of interest determination algorithm of lensless calcium imaging datasets
No full textAdvances in fluorescence imaging technology have been crucial to the progress of neuroscience. Whether it was specific expression of indicator proteins, detection of neurotransmitters, or miniaturization of fluorescence microscopes, fluorescence imaging has improved upon electrophysiology, the gold standard for monitoring brain activity, and enabled novel methods to sense activity in the brain. Hence, we developed a lightweight and compact implantable CMOS-based lensless Ca2+ imaging device for freely moving transgenic G-CaMP mouse experiments. However, without a lens system, determination of regions of interest (ROI) has proven challenging. Localization of fluorescence activity and separation of signal from noise are difficult. In this study, we report an ROI selection method using a series of adaptive binarizations with a gaussian method and morphological image processing. The parameters for each operation such as the kernel size, sigma and footprint size were optimized. We then validated the utility of the algorithm with simulated data and freely moving nociception experiments using the lensless devices. The device was implanted in the dorsal raphe nucleus to observe pain-related brain activity following a formalin test to stimulate pain. We observed significant increases in fluorescence activity after formalin injection compared to the control group when using the ROI determination algorithm.journal articl