Takeshi Koshiba

Prof. Takeshi Koshiba

Waseda University
orcid

Research Focus & Metrics

Academic Career Length

32Years (1995-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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18 April 2021 in Applied Sciences
Verified
Journal Article
Open access
PDF file
Faria SubahFaria Subah
Faria Subah
KDKaushik Deb
Kaushik Deb
PDPranab Kumar Dhar
Pranab Kumar Dhar
Takeshi KoshibaTakeshi Koshiba
Takeshi Koshiba
Autism spectrum disorder (ASD) is a complex and degenerative neuro-developmental disorder. Most of the existing methods utilize functional magnetic resonance imaging (fMRI) to detect ASD with a very limited dataset which provides high accuracy but results in poor generalization. To overcome this limitation and to enhance the performance of the automated autism diagnosis model, in this paper, we propose an ASD detection model using functional connectivity features of resting-state fMRI data. Our proposed model utilizes two commonly used brain atlases, Craddock 200 (CC200) and Automated Anatomical Labelling (AAL), and two rarely used atlases Bootstrap Analysis of Stable Clusters (BASC) and Power. A deep neural network (DNN) classifier is used to perform the classification task. Simulation results indicate that the proposed model outperforms state-of-the-art methods in terms of accuracy. The mean accuracy of the proposed model was 88%, whereas the mean accuracy of the state-of-the-art methods ranged from 67% to 85%. The sensitivity, F1-score, and area under receiver operating characteristic curve (AUC) score of the proposed model were 90%, 87%, and 96%, respectively. Comparative analysis on various scoring strategies show the superiority of BASC atlas over other aforementioned atlases in classifying ASD and control.

6 June 2013 in Physical Review A
Verified
Journal Article
Closed access
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TSTakahiro Sueki
Takahiro Sueki
Takeshi KoshibaTakeshi Koshiba
Takeshi Koshiba
TMTomoyuki Morimae
Tomoyuki Morimae
Blind quantum computation is a new quantum secure protocol, which enables Alice who does not have enough quantum technology to delegate her computation to Bob who has a fully fledged quantum power without revealing her input, output, and algorithm. So far, blind quantum computation has been considered only for the circuit model and the measurement-based model. Here we consider the possibility and the limitation of blind quantum computation in the ancilla-driven model, which is a hybrid of the circuit and the measurement-based models.

8 August 2022 in IEEE Access
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Journal Article
Open access
MKMd Kowsher
Md Kowsher
Abdullah As SamiAbdullah As Sami
Abdullah As Sami
NPNusrat Jahan Prottasha
Nusrat Jahan Prottasha
Mohammad Shamsul ArefinMohammad Shamsul Arefin
Mohammad Shamsul Arefin
PDPranab Kumar Dhar
Pranab Kumar Dhar
Takeshi KoshibaTakeshi Koshiba
Takeshi Koshiba
The advent of pre-trained language models has directed a new era of Natural Language Processing (NLP), enabling us to create powerful language models. Among these models, Transformer-based models like BERT have grown in popularity due to their cutting-edge effectiveness. However, these models heavily rely on resource-intensive languages, forcing other languages into multilingual models(mBERT). The two fundamental challenges with mBERT become significantly more challenging in a resource-constrained language like Bangla. It was trained on a limited and organized dataset and contained weights for all other languages. Besides, current research on other languages suggests that a language-specific BERT model will exceed multilingual ones. This paper introduces Bangla-BERTa, a monolingual BERT model for the Bangla language. Despite the limited data available for NLP tasks in Bangla, we perform pre-training on the largest Bangla language model dataset, BanglaLM, which we constructed using 40 GB of text data. Bangla-BERT achieves the highest results in all datasets and vastly improves the state-of-the-art performance in binary linguistic classification, multilabel extraction, and named entity recognition, outperforming multilingual BERT and other previous research. The pre-trained model is assessed against several non-contextual models such as Bangla fasttext and word2vec the downstream tasks. Finally, this model is evaluated by transfer learning based on hybrid deep learning models such as LSTM, CNN, and CRF in NER, and it is observed that Bangla-BERT outperforms state-of-the-art methods. The proposed Bangla-BERT model is assessed by using benchmark datasets, including Banfakenews, Sentiment Analysis on Bengali News Comments, and Cross-lingual Sentiment Analysis in Bengali. Finally, it is concluded that Bangla-BERT surpasses all prior state-of-the-art results by 3.52%, 2.2%, and 5.3%.

8 November 2013
Verified
Conference Paper
Open access
PDF file
MYMasaya Yasuda
Masaya Yasuda
TSTakeshi Shimoyama
Takeshi Shimoyama
JKJun Kogure
Jun Kogure
KYKazuhiro Yokoyama
Kazuhiro Yokoyama
Takeshi KoshibaTakeshi Koshiba
Takeshi Koshiba

13 June 2022 in Applied System Innovation
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Journal Article
Open access
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Behrouz ZolfaghariBehrouz Zolfaghari
Behrouz Zolfaghari
Takeshi KoshibaTakeshi Koshiba
Takeshi Koshiba
Recently, many researchers have been interested in the application of chaos in cryptography. Specifically, numerous research works have been focusing on chaotic image encryption. A comprehensive survey can highlight existing trends and shed light on less-studied topics in the area of chaotic image encryption. In addition to such a survey, this paper studies the main challenges in this field, establishes an ecosystem for chaotic image encryption, and develops a future roadmap for further research in this area.

18 April 2021 in Sensors
Verified
Journal Article
Open access
PDF file
Anik SenAnik Sen
Anik Sen
KDKaushik Deb
Kaushik Deb
PDPranab Kumar Dhar
Pranab Kumar Dhar
Takeshi KoshibaTakeshi Koshiba
Takeshi Koshiba
Recognizing the sport of cricket on the basis of different batting shots can be a significant part of context-based advertisement to users watching cricket, generating sensor-based commentary systems and coaching assistants. Due to the similarity between different batting shots, manual feature extraction from video frames is tedious. This paper proposes a hybrid deep-neural-network architecture for classifying 10 different cricket batting shots from offline videos. We composed a novel dataset, CricShot10, comprising uneven lengths of batting shots and unpredictable illumination conditions. Impelled by the enormous success of deep-learning models, we utilized a convolutional neural network (CNN) for automatic feature extraction, and a gated recurrent unit (GRU) to deal with long temporal dependency. Initially, conventional CNN and dilated CNN-based architectures were developed. Following that, different transfer-learning models were investigated—namely, VGG16, InceptionV3, Xception, and DenseNet169—which freeze all the layers. Experiment results demonstrated that the VGG16–GRU model outperformed the other models by attaining 86% accuracy. We further explored VGG16 and two models were developed, one by freezing all but the final 4 VGG16 layers, and another by freezing all but the final 8 VGG16 layers. On our CricShot10 dataset, these two models were 93% accurate. These results verify the effectiveness of our proposed architecture compared with other methods in terms of accuracy.