Auxiliary Features Research Articles

P.064 A case of late onset Pompe Disease presenting in 6th decade

Background: Late onset Pompe disease (LOPD), rare autosomal recessive lysosomal storage disease, resulting from mutation in alpha glucosidase enzyme (GAA) can present even in 6th decade of life. Slowly progressive, subtle, limb girdle pattern of weakness (LGPW), with auxiliary features such as ptosis, enlarged tongue, axial rigidity, facial diplegia, variable degree of respiratory weakness is not uncommon. Hypertrophic and electrical cardiac abnormalities are well described in LOPD. Methods: We present a case of 67-year-old male presenting with proximal weakness, subtle ptosis, bilateral quadriceps and shoulder girdle atrophy, and left toe numbness. PMHx: CABG, NSTEMI. Statin use. FMHx: noncontributory. Results: EMG: L5 radiculopathy, with unexpected myopathic units in hip/pelvic/ shoulder girdle muscles with active denervation and muscle irritability. CK, CRP, SPEP, ANA, LFTs, HMG-CoA reductase: normal. GAA enzymatic activity=0.96µmol/L/hr (low), genetics: pathogenic variants in GAA gene: c.-32-13T>G and c.1194+3G>C. ECHO: severe diastolic dysfunction, restrictive left ventricular filling. PFTs: normal. Diagnosed with LOPD, started on therapy. Conclusions: LOPD remains a differential for LGPW especially in older patient population with history of cardiopulmonary features. Age-appropriate conconminant pathologies may confound the diagnostic process.Symptoms may preceed diagnosis for years.GAA enzymatic activity followed by genetic testing remains readily available and can confirm diagnosis, preventing delay of approved therapy.

Object detection on low-resolution images with two-stage enhancement

Although deep learning-based object detection methods have achieved superior performance on conventional benchmark datasets, it is still difficult to detect objects from low-resolution (LR) images under diverse degradation conditions. To this end, a two-stage enhancement method for the LR image object detection (TELOD) framework is proposed. In the first stage, an extremely lightweight task disentanglement enhancement network (TDEN) is developed as a super-resolution (SR) sub-network before the detector. In the TDEN, the SR images can be obtained by applying the recurrent connection manner between an image restoration branch (IRB) and a resolution enhancement branch (REB) to enhance the input LR images. Specifically, the TDEN reduces the difficulty of image reconstruction by dividing the total image enhancement task into two sub-tasks, which are accomplished by the IRB and REB, respectively. Furthermore, a shared feature extractor is applied across two sub-tasks to explore common and accurate feature representations. In the second stage, an auxiliary feature enhancement head (AFEH) driven by high-resolution (HR) image priors is designed to improve the task-specific features produced by the detection Neck without any extra inference costs. In particular, the feature interaction module is built into the AFEH to integrate the features from the enhancement and detection phases to learn comprehensive information for detection. Extensive experiments show that the proposed TELOD significantly outperforms other methods. Specifically, the TELOD achieves mAP improvements of 1.8% and 3.3% over the second best method AERIS on degraded VOC and COCO datasets, respectively.

Ensembles of multiple models for soil moisture retrieval from remote sensing data over agricultural areas: A deep learning-based framework

In agricultural areas, most surface soil moisture (SM) retrieval models are unstable in terms of their accuracy and performance during crop growth. As a result, there is no consensus on which model performs optimally during the agricultural season. This is because of the uncertainties associated with model physics, initial conditions, model inversion processes, input data, vegetation attenuation and soil characteristics. To better deal with these practical concerns, we propose a simple, but robust SM retrieval method of using combination of multiple models based on deep learning and multi-model ensemble approach, called the DL-MME method, which makes use of the ‘collective intelligence’ and ‘wisdom of crowds’ concepts. The advantages of this method are: (1) robustness to model selection, and (2) robustness to model calibration during the growing season. In addition, this method is less dependent on one type of data across various agricultural areas compared to the single model approach. Firstly, the coupled water cloud model (WCM) and soil backscattering models (Oh model or advanced integral equation model (AIEM)) with different vegetation descriptors were calibrated and validated during the growing season in sugarcane and winter wheat fields for Sentinel-1 backscattering coefficients (VV and VH). SM was also retrieved by employing the trapezoid model (OPTRAM) with different parameters from Sentinel-2 images. To optimize SM retrieval computations, we used the outputs from optical and SAR models, auxiliary features, and reliable in situ SM measurements as inputs to a deep learning convolutional neural network (DL-CNN). For sugarcane and wheat fields in the early stages of crop growth, WCM models retrieved more accurate time-series SM than optical models. OPTRAM soil moisture retrievals showed greater accuracy in the late crop growing season. Time-series SM retrieval accuracy using DL-MME was higher than for the optical and semi-empirical SAR models. According to the results of the in situ validation for wheat (sugarcane) fields, the minimum MAE by an optimal combination of models was around 0.01 (0.02) m3m−3 (RMSE = 0.036 (0.074) m3m−3; R = 0.87 (0.71)). The findings demonstrate that our method is reliable and feasible for SM retrieval. Additionally, our method provides a way to select an optimal model for retrieving time-series SM during the crop growing season.

Deep Representation Learning With Sample Generation and Augmented Attention Module for Imbalanced ECG Classification.

Developing an efficient heartbeat monitoring system has become a focal point in numerous healthcare applications. Specifically, in the last few years, heartbeat classification for arrhythmia detection has gained considerable interest from researchers. This paper presents a novel deep representation learning method for the efficient detection of arrhythmic beats. To mitigate the issues associated with the imbalanced data distribution, a novel re-sampling strategy is introduced. Unlike the existing oversampling methods, the proposed technique transforms majority-class samples into minority-class samples with a novel translation loss function. This approach assists the model in learning a more generalized representation of crucially important minority class samples. Moreover, by exploiting an auxiliary feature, an augmented attention module is designed that focuses on the most relevant and target-specific information. We adopted an inter-patient classification paradigm to evaluate the proposed method. The experimental results of this study on the MIT-BIH arrhythmia database clearly indicate that the proposed model with augmented attention mechanism and over-sampling strategy significantly learns a balanced deep representation and improves the classification performance of vital heartbeats.

Dual-phase prediction model of passenger thermal sensation using facial thermal imaging and environmental factors

The concept of passenger-centric design has become increasingly significant in the intelligent automotive industry. Enhancing in-cabin thermal comfort while maintaining energy efficiency is crucial, and to this end, we leverage real-time passenger thermal sensation as a basis for HVAC control strategies. This study introduces a non-invasive, dual-phase prediction model that evaluates passenger thermal comfort by utilizing facial thermal imaging and environmental factors. The proposed model employs a deep learning neural network to extract pertinent features from the facial thermal images for an initial prediction. Then this prediction is refined by integrating it with environmental data through a machine learning algorithm, facilitating real-time personal thermal comfort assessment. Data collection for the model was performed across two distinct seasons, with 22 participants in summer and 18 in winter, gathering facial thermal images, environmental parameters, and thermal sensation votes to construct a comprehensive dataset. Analysis revealed a set of critical environmental factors that correlate strongly with thermal sensation votes, which were used as auxiliary features in the model. The performance of the proposed dual-phase approach, combining deep learning and machine learning techniques, demonstrated robust effectiveness on both summer and winter datasets. This substantiates the method's practicality for real-world application within vehicle environments.

MCT-VHD: Multi-modal contrastive transformer for video highlight detection

Autonomous highlight detection aims to identify the most captivating moments in a video, which is crucial for enhancing the efficiency of video editing and browsing on social media platforms. However, current efforts primarily focus on visual elements and often overlook other modalities, such as text information that could provide valuable semantic signals. To overcome this limitation, we propose a Multi-modal Contrastive Transformer for Video Highlight Detection (MCT-VHD). This transformer-based network mainly utilizes video and audio modalities, along with auxiliary text features (if exist) for video highlight detection. Specifically, We enhance the temporal connections within the video by integrating a convolution-based local enhancement module into the transformer blocks. Furthermore, we explore three multi-modal fusion strategies to improve highlight inference performance and employ a contrastive objective to facilitate interactions between different modalities. Comprehensive experiments conducted on three benchmark datasets validate the effectiveness of MCT-VHD, and our ablation studies provide valuable insights into its essential components.

Multi-scale feature aggregation and fusion network with self-supervised multi-level perceptual loss for textures preserving low-dose CT denoising

Objective. The textures and detailed structures in computed tomography (CT) images are highly desirable for clinical diagnosis. This study aims to expand the current body of work on textures and details preserving convolutional neural networks for low-dose CT (LDCT) image denoising task. Approach. This study proposed a novel multi-scale feature aggregation and fusion network (MFAF-net) for LDCT image denoising. Specifically, we proposed a multi-scale residual feature aggregation module to characterize multi-scale structural information in CT images, which captures regional-specific inter-scale variations using learned weights. We further proposed a cross-level feature fusion module to integrate cross-level features, which adaptively weights the contributions of features from encoder to decoder by using a spatial pyramid attention mechanism. Moreover, we proposed a self-supervised multi-level perceptual loss module to generate multi-level auxiliary perceptual supervision for recovery of salient textures and structures of tissues and lesions in CT images, which takes advantage of abundant semantic information at various levels. We introduced parameters for the perceptual loss to adaptively weight the contributions of auxiliary features of different levels and we also introduced an automatic parameter tuning strategy for these parameters. Main results. Extensive experimental studies were performed to validate the effectiveness of the proposed method. Experimental results demonstrate that the proposed method can achieve better performance on both fine textures preservation and noise suppression for CT image denoising task compared with other competitive convolutional neural network (CNN) based methods. Significance. The proposed MFAF-net takes advantage of multi-scale receptive fields, cross-level features integration and self-supervised multi-level perceptual loss, enabling more effective recovering of fine textures and detailed structures of tissues and lesions in CT images.

Multi-source self-supervised domain adaptation network for VRLA battery anomaly detection of data center under non-ideal conditions

As the key component of uninterruptible power supply, the anomaly detection of valve-regulated lead-acid (VRLA) batteries is the reliable guarantee for the operation of internet data centers. Although deep neural networks (DNNs) have been investigated in battery anomaly detection, the key problem of feature learning under non-ideal conditions, i.e., data scarcity and class-imbalance, is not addressed very well. In this article, a novel DNN called multi-source self-supervised domain adaptation network (MSSSDAN) is proposed for VRLA battery anomaly detection of data center under non-ideal conditions. Firstly, multi-dimensional collaborative self-supervised learning (MDCSSL) is proposed to address the class-imbalanced problem by performing auxiliary feature learning task considering the temporal dependency of different channels. Secondly, a novel transfer learning (TL) framework, multi-source adaptive transfer learning (MSATL) is developed to solve the domain shift problem by adaptively minimizing the distribution discrepancy of different domains. Finally, the outperformance of MSSSDAN is verified on the VRLA battery dataset collected from Tencent data center. The testing results demonstrate that MSSSDAN can effectively solve the problem of battery anomaly detection under non-ideal conditions.

Log2Graph: A graph convolution neural network based method for insider threat detection

With the advancement of network security equipment, insider threats gradually replace external threats and become a critical contributing factor for cluster security threats. When detecting and combating insider threats, existing methods often concentrate on users’ behavior and analyze logs recording their operations in an information system. Traditional sequence-based method considers temporal relationships for user actions, but cannot represent complex logical relationships well between various entities and different behaviors. Current machine learning-based approaches, such as graph-based methods, can establish connections among log entries but have limitations in terms of complexity and identifying malicious behavior of user’s inherent intention. In this paper, we propose Log2Graph, a novel insider threat detection method based on graph convolution neural network. To achieve efficient anomaly detection, Log2Graph first retrieves logs and corresponding features from log files through feature extraction. Specifically, we use an auxiliary feature of anomaly index to describe the relationship between entities, such as users and hosts, instead of establishing complex connections between them. Second, these logs and features are augmented through a combination of oversampling and downsampling, to prepare for the next-stage supervised learning process. Third, we use three elaborated rules to construct the graph of each user by connecting the logs according to chronological and logical relationships. At last, the dedicated built graph convolution neural network is used to detect insider threats. Our validation and extensive evaluation results confirm that Log2Graph can greatly improve the performance of insider threat detection compared to existing state-of-the-art methods.

Deciphering three predominant biopsy-proven phenotypes of IgG4-associated kidney disease: a retrospective study.

IgG4-associated kidney disease (IgG4-RKD) encompasses a spectrum of disorders, predominantly featuring tubulointerstitial nephritis (TIN) and membranous glomerulonephropathy (MGN). The limited understanding of the co-occurrence of IgG4-RD-TIN with anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) poses a diagnostic and therapeutic challenge. We examined 49 cases, comprising 21 cases of IgG4-RD-TIN (group A), 10 cases of IgG4-RD-TIN accompanied with MGN (group B), and 18 cases of IgG4-RD-TIN concurrent with AAV (group C), at the First Affiliated Hospital of Zhejiang University, China, from June 2015 to December 2022. The mean age and gender of the three IgG4-RKD subtypes were not statistically significant. IgG4-RD-TIN exhibited higher serum creatinine and a higher incidence of hypocomplementemia (group A 47.6%, group B 30%, group C 16.7%). IgG4-RD-TIN-MGN was characterized by proteinuria (group A 0.3g/d, group B 4.0g/d, group C 0.8g/d, P<0.001) and hypoalbuminemia. IgG4-RD-TIN-AAV exhibited hypohemoglobinemia (group A 103.45g/l, group B 119.60g/l, group C 87.94g/l, P<0.001) and a high level of urine erythrocytes. The primary treatment for IgG4-RD-TIN was steroids alone, whereas IgG4-RD-TIN-MGN and IgG4-RD-TIN-AAV necessitated combination therapy. Group A experienced two relapses, whereas groups B and C had no relapses. There was no significant difference in patient survival among the three groups, and only two cases in group C suffered sudden death. This study provides valuable insights into clinical manifestations, auxiliary examination features, pathological characteristics, and prognosis of IgG4-RD-TIN, IgG4-RD-TIN-MGN, and IgG4-RD-TIN concurrent AAV. Large-scale studies are required to validate these findings.

BVA-Transformer: Image-text multimodal classification and dialogue model architecture based on Blip and visual attention mechanism

Multimodal tasks have become a hot research direction in recent years. The emergence of large-scale models has gradually elevated the extensive multimodal tasks, achieving remarkable achievements. However, when it comes to fusing multiple modalities for multimodal tasks, how to better integrate multimodal features is still a problem worth exploring. In tasks such as sentiment analysis targeting a wide range of social media content, the use of features derived solely from the [CLS] token may lead to insufficient information. This paper proposes BVA-Transformer model architecture for image-text multimodal classification and dialogue, which incorporates the EF-CaTrBERT method for feature fusion and introduces BLIP for the transformation of images to the textual space. This enables the fusion of images and text in the same information space, avoiding issues of information redundancy and conflict compared to traditional feature fusion methods. In addition, we proposed a Global Features Encoder (GFE) module based on visual attention in the BVA-Transformer, which can provide more global and targeted auxiliary features for the [CLS] token. This enables the model to utilize more feature information in classification tasks under this feature fusion method and dynamically select information to focus on. We also introduced the Trv structure from EVA-02 in the Decoder part of BVA-Transformer, investigating its impact on the model performance. Furthermore, we designed a three-stage training to further enhance the model’s performance. Experimental results demonstrate that BVA-Transformer achieves high-quality classification while generating dialogue sentences. Compared to existing multimodal classification models on our validation dataset, it exhibits excellent performance.

Contextualized Satire Detection in Short Texts Using Deep Learning Techniques

Satire is prominent in user-generated content on various online platforms in the form of satirical news, customer reviews, blogs, articles, and short messages that are typically of an informal nature. As satire is also used to disseminate false information on the Internet, its computational detection has become a well-known issue. Existing work focuses primarily on formal document- or sentence-level textual data, whereas informal short texts have gotten less attention for satire detection. This paper presents a new model called BiLSTM self-attention (BiSAT) for detecting satire in informal short texts. It consists of various components such as input, embedding, self-attention, and two bi-directional long short-term memory (BiLSTM) layers for learning crucial contextual information pertaining to the satire present in the texts. The input layer uses the text as input to create an input vector, which is then given to the embedding layer to create the appropriate numeric vector. The output of the embedding layer is passed on to the first BiLSTM layer, which extracts contextual information-based sequences in the opposite direction. Between the first and second BiLSTM layers, a self-attention layer is employed to draw attention to the important satirical information that is acquired by the hidden layer of the first BiLSTM. The BiSAT model also takes a classic feature engineering approach, employing a 13-dimensional auxiliary feature vector comprised of features from four separate feature categories: sentiment, punctuation, hyperbole, and affective. The proposed BiSAT model is empirically evaluated on two benchmark datasets and a newly created dataset called Satire-280. It outperforms existing research and baseline methods by a significant margin. The Satire-280 dataset along with code can be downloaded from GitHub repository: https://github.com/Ashraf-Kamal/Satire-Detection.

CIDR: A Cooperative Integrated Dynamic Refining Method for Minimal Feature Removal Problem

The minimal feature removal problem in the post-hoc explanation area aims to identify the minimal feature set (MFS). Prior studies using the greedy algorithm to calculate the minimal feature set lack the exploration of feature interactions under a monotonic assumption which cannot be satisfied in general scenarios. In order to address the above limitations, we propose a Cooperative Integrated Dynamic Refining method (CIDR) to efficiently discover minimal feature sets. Specifically, we design Cooperative Integrated Gradients (CIG) to detect interactions between features. By incorporating CIG and characteristics of the minimal feature set, we transform the minimal feature removal problem into a knapsack problem. Additionally, we devise an auxiliary Minimal Feature Refinement algorithm to determine the minimal feature set from numerous candidate sets. To the best of our knowledge, our work is the first to address the minimal feature removal problem in the field of natural language processing. Extensive experiments demonstrate that CIDR is capable of tracing representative minimal feature sets with improved interpretability across various models and datasets.

FD3D: Exploiting Foreground Depth Map for Feature-Supervised Monocular 3D Object Detection

Monocular 3D object detection usually adopts direct or hierarchical label supervision. Recently, the distillation supervision transfers the spatial knowledge from LiDAR- or stereo-based teacher networks to monocular detectors, but remaining the domain gap. To mitigate this issue and pursue adequate label manipulation, we exploit Foreground Depth map for feature-supervised monocular 3D object detection named FD3D, which develops the high-quality instructive intermediate features to conduct desirable auxiliary feature supervision with only the original image and annotation foreground object-wise depth map (AFOD) as input. Furthermore, we build up our instructive feature generation network to create instructive spatial features based on the sufficient correlation between image features and pre-processed AFOD, where AFOD provides the attention focus only on foreground objects to achieve clearer guidance in the detection task. Moreover, we apply the auxiliary feature supervision from the pixel and distribution level to achieve comprehensive spatial knowledge guidance. Extensive experiments demonstrate that our method achieves state-of-the-art performance on both the KITTI and nuScenes datasets, with no external data and no extra inference computational cost. We also conduct quantitative and qualitative studies to reveal the effectiveness of our designs.

Complementary Knowledge Distillation for Robust and Privacy-Preserving Model Serving in Vertical Federated Learning

Vertical Federated Learning (VFL) enables an active party with labeled data to enhance model performance (utility) by collaborating with multiple passive parties that possess auxiliary features corresponding to the same sample identifiers (IDs). Model serving in VFL is vital for real-world, delay-sensitive applications, and it faces two major challenges: 1) robustness against arbitrarily-aligned data and stragglers; and 2) privacy protection, ensuring minimal label leakage to passive parties. Existing methods fail to transfer knowledge among parties to improve robustness in a privacy-preserving way. In this paper, we introduce a privacy-preserving knowledge transfer framework, Complementary Knowledge Distillation (CKD), designed to enhance the robustness and privacy of multi-party VFL systems. Specifically, we formulate a Complementary Label Coding (CLC) objective to encode only complementary label information of the active party's local model for passive parties to learn. Then, CKD selectively transfers the CLC-encoded complementary knowledge 1) from the passive parties to the active party, and 2) among the passive parties themselves. Experimental results on four real-world datasets demonstrate that CKD outperforms existing approaches in terms of robustness against arbitrarily-aligned data, while also minimizing label privacy leakage.

Enhancing vegetation formation classification: Integrating coarse-scale traditional mapping knowledge and advanced machine learning

Mapping vegetation formation types in large areas is crucial for ecological and environmental studies. However, this is still challenging to distinguish similar vegetation formation types using existing predictive vegetation mapping methods, based on commonly used environmental variables and remote sensing spectral data, especially when there are not enough training samples. To solve this issue, we proposed a predictive vegetation mapping method by integrating an advanced machine learning algorithm and knowledge in an early coarse-scale vegetation map (VMK). First, we implemented classification using the random forest algorithm by integrating the early vegetation map as an auxiliary feature (VMF). Then, we determined the rationality of classified vegetation types and distinguished the confusing types, respectively, based on the knowledge of the spatial distributions and hierarchies of vegetation. Finally, we replaced each recognized unreasonable vegetation type with its corresponding reasonable vegetation type. We implemented the new method in upstream of the Yellow River based on GaoFen-1 satellite images and other environmental variables (i.e., topographical and climate variables). Results showed that the overall accuracy using the VMK method ranged from 67.7 % to 76.8 %, which was 10.9 % to 13.4 % and 3.2 % to 6.6 %, respectively, higher than that of the method without the early vegetation map (NVM) and the VMF method, based on cross-validation with 20 % to 60 % random training samples. The spatial details of the vegetation map using the VMK method were also more reasonable compared to the NVM and VMF methods. These results indicated that the VMK method can distinctly improve the mapping accuracy at the vegetation formation level by integrating knowledge of existing vegetation maps. The proposed method can largely reduce the requirements on the number of field samples, which is especially important for alpine mountains and arctic region, where collecting training samples is more difficult due to the harsh natural environment.

Multi-faceted spatio-temporal network for weather-aware air traffic flow prediction in multi-airport system

As one of the core modules for air traffic flow management, Air Traffic Flow Prediction (ATFP) in the Multi-Airport System (MAS) is a prerequisite for demand and capacity balance in the complex meteorological environment. Due to the challenge of implicit interaction mechanism among traffic flow, airspace capacity and weather impact, the Weather-aware ATFP (Wa-ATFP) is still a nontrivial issue. In this paper, a novel Multi-faceted Spatio-Temporal Graph Convolutional Network (MSTGCN) is proposed to address the Wa-ATFP within the complex operations of MAS. Firstly, a spatio-temporal graph is constructed with three different nodes, including airport, route, and fix to describe the topology structure of MAS. Secondly, a weather-aware multi-faceted fusion module is proposed to integrate the feature of air traffic flow and the auxiliary features of capacity and weather, which can effectively address the complex impact of severe weather, e.g., thunderstorms. Thirdly, to capture the latent connections of nodes, an adaptive graph connection constructor is designed. The experimental results with the real-world operational dataset in Guangdong-Hong Kong-Macao Greater Bay Area, China, validate that the proposed approach outperforms the state-of-the-art machine-learning and deep-learning based baseline approaches in performance. The case study of convective weather scenarios further proves the adaptability of the proposed approach.

Local feature expansion Vision Transformer model for bearing fault diagnosis under noise environments

Vision Transformer (ViT) shows potential in bearing fault diagnosis due to its multi-head self-attention mechanism and parallel feature extraction network which are efficient to achieve the robust complete feature representation of the fault. However, its adaption to the noise interference relies on the sufficient huge amount of training samples to prepare the local features of the fault and may suffer performance degradation when only a limited number of samples are available for the model training. To combat this challenge, an improved ViT diagnosis model based on the local feature expansion, i.e., LFE-ViT, is proposed. An auxiliary feature extraction block is introduced using a local feature expansion network and works as a parallel module with the ViT encoder. Through the enlargement of the receptive field, the multi-scale local features on a high dimensional space are available upon the limited samples. Then, through a feature embedding channel, the extracted local features are transmitted to the ViT encoder. Finally, by virtue of the multi-head self-attention mechanism to capture the time sequence global information, a fault diagnosis model comprising comprehensively local and global feature information is derived. Experimental validation on the bearing fault dataset from Case Western Reserve University shows that LFE-ViT has provided a rather satisfactory diagnosis performance under limited samples and noise environment.

Auxiliary feature extractor and dual attention-based image captioning

Auxiliary feature extractor and dual attention-based image captioning

Impact of Auxiliary Features on Retention of Short Dental Crowns: An In-Vitro Analysis of Box and Groove Preparations.

BACKGROUND Several auxiliary features have been proposed to achieve sustainable retention for short-prepared dental crowns; however, achieving retention is challenging. This study aimed to assess the impact of increased total occlusal convergence and auxiliary preparation factors like box and groove on the retention form of short tooth preparations. MATERIAL AND METHODS Eighty resin machine-milled dies with a height of 3 mm and a deep chamfer margin of 1 mm were prepared to mimic the short-prepared molar. Initially, 2 teeth were prepared following the guidelines, and the total occlusal convergence was kept at 10° and 20°, respectively. Auxiliary features such as the proximal box and buccal groove were prepared on separate 20° dies. Eighty dies were prepared with 10 samples each for 10°, 20°, 20° with proximal box and 20° with buccal groove for zirconia (n=40) and metal crowns (n=40). Cementation was done with glass ionomer luting cement, and a pull-off test was conducted. Data were analyzed using one-way analysis of variance and post hoc fisher least significant difference test (P<0.05). RESULTS The highest mean was observed in the proximal box group with the metal crown (14.59), and the lowest in the group with 20° zirconia crowns (9.12). Within groups, the highest retentive values were found for the 20° taper with proximal box preparation; the lowest was for the 20° taper group. CONCLUSIONS Within the study limitations, it could be concluded that incorporating a proximal box or buccal groove in short tooth preparations with an increased total occlusal convergence improved retentive values.