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Rupam Mukherjee

Publications and source records attributed to Rupam Mukherjee.

4 recordsLinked to original sources

Uncertainty-Aware Multimodal Fusion for Oral Lesion Classification

Early detection of oral cancer and potentially malignant diseases is a major challenge in low-resource settings due to the scarcity of annotated data. We provide a unified approach for oral lesion classification that incorporates deep learning, spectral analysis, and demographic data. A pathologist verified subset of oral cavity images was curated from a publicly available dataset. Oral cavity pictures were processed using a fine tuned ConvNeXtv2 network for deep embeddings before being translated into the hyperspectral domain using a reconstruction algorithm. Haemoglobin sensitive, textural, and spectral descriptors were obtained from the reconstructed hyperspectral cubes and combined with demographic data. Multiple machine learning models were evaluated using patient specific validation. Finally, an incremental heuristic meta learner (IHML) was developed that merged calibrated base classifiers via probabilistic feature stacking and uncertainty-aware abstraction of multimodal representations with patient level smoothing. By decoupling evidence extraction from decision fusion, IHML stabilizes predictions in heterogeneous, small sample medical datasets. On an unseen test set, our proposed model achieved a macro F1 of 66.23% and an overall accuracy of 64.56%. The findings demonstrate that RGB to hyperspectral reconstruction and ensemble meta learning improve diagnostic robustness in real world oral lesion screening.

eess.IV

RAA-MIL: A Novel Framework for Classification of Oral Cytology

Cytology is a valuable tool for early detection of oral squamous cell carcinoma (OSCC). However, manual examination of cytology whole slide images (WSIs) is slow, subjective, and depends heavily on expert pathologists. To address this, we introduce the first weakly supervised deep learning framework for patient-level diagnosis of oral cytology whole slide images, leveraging the newly released Oral Cytology Dataset [1], which provides annotated cytology WSIs from ten medical centres across India. Each patient case is represented as a bag of cytology patches and assigned a diagnosis label (Healthy, Benign, Oral Potentially Malignant Disorders (OPMD), OSCC) by an in-house expert pathologist. These patient-level weak labels form a new extension to the dataset. We evaluate a baseline multiple-instance learning (MIL) model and a proposed Region-Affinity Attention MIL (RAA-MIL) that models spatial relationships between regions within each slide. The RAA-MIL achieves an average accuracy of 72.7%, weighted F1-score of 0.69 on an unseen test set, outperforming the baseline. This study establishes the first patient-level weakly supervised benchmark for oral cytology and moves toward reliable AI-assisted digital pathology.

eess.IV

Enhancement of high dielectric constant in CaCu$_3$Ti$_4$O$_1$$_2$/RuO$_2$ composites in the vicinity of the percolation threshold

We observe the large enhancement in the dielectric response near the percolation threshold in a composite nanoparticle system consisting of metallic RuO$_2$ grains embedded into dielectric CaCu$_3$Ti$_4$O$_1$$_2$ (CCTO) matrix and annealed at 1100OC. To understand the nature of the dielectric response, we compare CCTO fabricated by two different techniques, solid state process (CCTO$_S$$_S$) and sol-gel process (CCTO$_S$$_G$) with the intrinsic dielectric constant in both cases found to be on the order of 10$^3$-10$^4$ at 10 kHz. For RuO$_2$/CCTO$_S$$_S$ and RuO$_2$/CCTO$_S$$_G$ composites and composites, an increase of the dielectric constant by factors of 7 and 5 respectively is observed in the vicinity of the percolation threshold of about 0.1, with moderate losses at room temperature. Scanning electron microscopy and Energy Dispersive X-ray spectroscopy indicate that the difference in the size of the effect may arise from the microstructure of the copper oxide enriched grain boundaries in the host CCTO.

cond-mat.mtrl-sci

Oxygen vacancy enhanced room temperature ferromagnetism in Al-doped MgO nanoparticles

We have investigated the room temperature ferromagnetic order that develops in Al-substituted magnesium oxide, Mg(Al)O, nanoparticles with Al fractions of up to 5 at.%. All samples, including undoped MgO nanoparticles, exhibit room temperature ferromagnetism, with the saturation magnetization reaching a maximum of 0.023 emu/g at 2 at.% of Al. X-ray photoelectron spectroscopy identifies the presence of oxygen vacancies in both doped and undoped MgO nanoparticles, with the vacancy concentration increasing upon vacuum annealing of Mg(Al)O, resulting in two-fold enhancement of the saturation magnetization for 2 at.% Al-doped MgO. Our results suggest that the oxygen vacancies are largely responsible for room temperature ferromagnetism in MgO.

cond-mat.mtrl-sci