Muthukumar K.A.

Dr. Muthukumar K.A.

Keio University, Tokyo, Japan
orcid

Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

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

Representative Publications

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1 January 2021 in IEEE Access
Verified
Journal Article
Open access
MKMuthukumar K.A.
Muthukumar K.A.
Mondher BouaziziMondher Bouazizi
Mondher Bouazizi
Tomoaki OhtsukiTomoaki Ohtsuki
Tomoaki Ohtsuki
In this paper, we propose a deep learning-based technique for activity detection that uses wide-angle low-resolution infrared (IR) array sensors. Alongside with the main challenge which is how to further improve the performance of IR array sensor-based methods for activity detection, throughout this work, we address the following challenges: we employ a wide-angle infrared array sensor with peripheral vision in comparison to a standard IR array sensor. This makes activities at different positions have different patterns of temperature distribution, making it challenging to learn these different patterns. In addition, unlike previous works, our goal is to perform the activity detection using the least possible amount of information. While the conventional works use a time window equal to 10 seconds where a single event occurs, we aim to identify the activity using a time window of less than 1 second. Nevertheless, we aim to improve over the accuracy obtained in previous work by employing deep learning, while keeping the approach light for it to run on devices with low computational power. Therefore, we use a hybrid deep learning model well suited for the classification of distorted images because the neural network learns the features automatically. In our work, we use two IR sensors ( 32×24 pixels), one placed on the wall and one on the ceiling. We collect data simultaneously from both the IR sensors and apply hybrid deep learning classification techniques to classify various activities including “walking”, “standing”, “sitting”, “lying”, “falling”, and the transition between the activities which is referred to as “action change”. This is done in two steps. In the first step, we classify ceiling data and wall data separately as well as the combination of both (ceiling and wall) using a Convolutional Neural Network (CNN). In the second step, the output of the CNN is fed to a Long Short Term Memory (LSTM) with a window size equal to 5 frames to classify the sequence of activities. Through experiments, we show that the classification accuracy of the ceiling data, wall data, and combined data with the LSTM reach 0.96, 0.95, and 0.97, respectively.

5 February 2025 in Scientific Reports
Verified
Journal Article
Open access
PDF file
MKMuthukumar K.A.
Muthukumar K.A.
DNDhruva Nandi
Dhruva Nandi
PRPriya Ranjan
Priya Ranjan
KRKrithika Ramachandran
Krithika Ramachandran
SPShiny Pj
Shiny Pj
RJRajiv Janardhanan
Rajiv Janardhanan
Cardiovascular diseases (CVD) are a predominant health concern globally, emphasizing the need for advanced diagnostic techniques. In our research, we present an avant-garde methodology that synergistically integrates ECG readings and retinal fundus images to facilitate the early disease tagging as well as triaging of the CVDs in the order of disease priority. Recognizing the intricate vascular network of the retina as a reflection of the cardiovascular system, alongwith the dynamic cardiac insights from ECG, we sought to provide a holistic diagnostic perspective. Initially, a Fast Fourier Transform (FFT) was applied to both the ECG and fundus images, transforming the data into the frequency domain. Subsequently, the Earth Mover’s Distance (EMD) was computed for the frequency-domain features of both modalities. These EMD values were then concatenated, forming a comprehensive feature set that was fed into a Neural Network classifier. This approach, leveraging the FFT’s spectral insights and EMD’s capability to capture nuanced data differences, offers a robust representation for CVD classification. Preliminary tests yielded a commendable accuracy of 84%, underscoring the potential of this combined diagnostic strategy. As we continue our research, we anticipate refining and validating the model further to enhance its clinical applicability in resource limited healthcare ecosystems prevalent across the Indian sub-continent and also the world at large.

20 May 2022 in Sensors
Verified
Journal Article
Open access
PDF file
MKMuthukumar K.A.
Muthukumar K.A.
Mondher BouaziziMondher Bouazizi
Mondher Bouazizi
Tomoaki OhtsukiTomoaki Ohtsuki
Tomoaki Ohtsuki
In this paper, we propose an activity detection system using a 24 × 32 resolution infrared array sensor placed on the ceiling. We first collect the data at different resolutions (i.e., 24 × 32, 12 × 16, and 6 × 8) and apply the advanced deep learning (DL) techniques of Super-Resolution (SR) and denoising to enhance the quality of the images. We then classify the images/sequences of images depending on the activities the subject is performing using a hybrid deep learning model combining a Convolutional Neural Network (CNN) and a Long Short-Term Memory (LSTM). We use data augmentation to improve the training of the neural networks by incorporating a wider variety of samples. The process of data augmentation is performed by a Conditional Generative Adversarial Network (CGAN). By enhancing the images using SR, removing the noise, and adding more training samples via data augmentation, our target is to improve the classification accuracy of the neural network. Through experiments, we show that employing these deep learning techniques to low-resolution noisy infrared images leads to a noticeable improvement in performance. The classification accuracy improved from 78.32% to 84.43% (for images with 6 × 8 resolution), and from 90.11% to 94.54% (for images with 12 × 16 resolution) when we used the CNN and CNN + LSTM networks, respectively.

19 December 2024 in Discover Food
Verified
Journal Article
Open access
PDF file
MKMuthukumar K.A.
Muthukumar K.A.
SGSoumya Gupta
Soumya Gupta
DSDoli Saikia
Doli Saikia
The global shift towards plant-based diets, particularly in India, is driven by environmental and ethical considerations. While plant foods are often regarded as more sustainable, concerns persist regarding protein quality, especially after processing. With protein deficiencies being prevalent among Indians, it is crucial to understand the impact of food processing on nutrient retention. This research integrates machine learning with food science to develop a comprehensive AI framework for forecasting the protein content of various plant-based sources following both traditional and non-conventional processing methods. A robust database was compiled using sources such as Web of Science, Scopus, PubMed, and Google Scholar, covering a wide range of plant-based foods and their protein content before and after processing. After data preprocessing, two primary machine learning algorithms were employed: Support Vector Regression (SVR) and Random Forest (RF), both implemented using Scikit-learn. The SVR model was optimized to identify the best-fitting hyperplane in high-dimensional space, while the RF model utilized GridSearchCV for hyperparameter tuning and performed a “Feature Importance Analysis” to identify key factors influencing the outcomes. Model performance was evaluated using Normalized Mean Squared Error (NMSE) as the evaluation metric. The results indicated that the RF model achieved an NMSE of approximately 0.35, reflecting a moderate level of prediction error relative to data variance. In contrast, the SVR model significantly outperformed the RF model, with an NMSE of approximately 0.03, demonstrating superior accuracy and efficiency in predicting nutrient retention. This study leverages machine learning to bridge a critical gap in understanding nutrient retention in plant-based foods during processing. The findings reveal that the SVR model is particularly effective in predicting nutrient retention, outperforming the RF model. This novel approach holds significant potential to optimize nutrient retention in plant-based food products, offering important implications for public health and food quality.

11 December 2020 in Materials Today: Proceedings
Verified
Journal Article
Closed access
MKMuthukumar K.A.
Muthukumar K.A.
KVK. VinothKumar
K. VinothKumar
DHD. Hepsiba
D. Hepsiba
LTLogeswaran Thangamuthu
Logeswaran Thangamuthu
BGB. Gunapriya
B. Gunapriya
CGC. Gokul
C. Gokul

5 January 2021 in Materials Today: Proceedings
Verified
Journal Article
Closed access
MKMuthukumar K.A.
Muthukumar K.A.
TJT. Jishin Jayan
T. Jishin Jayan
CSC. Sridhar
C. Sridhar