"No one is harder on a talented person than the person themselves" - Linda Wilkinson ; "Trust your guts and don't follow the herd" ; "Validate direction not destination" ;
Showing posts with label Research Papers. Show all posts
Showing posts with label Research Papers. Show all posts

August 20, 2023

Plant Identification Using Convolution Neural Network and Vision Transformer-Based Models

Recently, my team published a vision paper, providing valuable insights and lessons which will benefit our future work. Here I highlight those key experiences and challenges: 

Plant Identification Using Convolution Neural Network and Vision Transformer-Based Models

  • First, we grappled with open-ended questions in our problem statement, requiring us to think critically and flexibly.
  • Second, we used past experiences, research approaches, and current vision models to craft our unique approach for this paper.
  • Third, was the phase of experimenting which we had to analyze, timebox, and finalize.
  • We also faced data challenges, drawing inspiration from similar research papers to overcome this hurdle.
  • An important achievement for us was reaching state-of-art accuracy in our findings.
  • We considered the scalability of our approach, contemplating how it can be implemented as we include multiple categories/classes.
  • Focus was directed toward developing a repeatable architecture and effectively capturing feedback for continuous improvement.
  • A significant portion of our time was dedicated to extensive documentation, conducting numerous experiments, and evaluating metrics.
  • We navigated through the publication process, ensuring our work reached the right platforms.
  • Lastly, we sought collaboration with like-minded clients, with whom we could work on making our learning reusable.

This experience has been thoroughly enriching for our team and we remain excited about our journey ahead

Keep Learning!!!

July 30, 2022

Catalog management - Papers Read

Deep Learning for Automated Tagging of Fashion Images

  • We present 9 deep learning classifiers to predict Fashion attributes in 4 different categories: apparel (dresses and tops), shoes, watches and luggages.
  • By extracting these tags or attributes from fashion images, queries to the products catalogue can be generated looking for similar or complementary products, produce recommendations for the user, fill missing metadata, and overall provide an improved search experience



Tiered Deep Similarity Search for Fashion

  • We propose a new attribute-guided metric learning (AGML) with multitask CNNs that jointly learns fashion attributes and image embeddings


FashionSearchNet: Fashion Search with Attribute Manipulation

  • The focus of this paper is on retrieval of fashion images after manipulating attributes of the query images.

Keep Exploring!!!

February 10, 2022

Fashion Segmentation Paper Read

Paper - U2-Net: Going Deeper with Nested U-Structure for Salient Object Detection

Key Notes

  • Capture more contextual information from different scales thanks
  • Code link https://github.com/xuebinqin/U-2-Net
  • Segmenting the most visually attractive objects in an image
  • Deep features extracted by existing backbones, such as Alexnet [17], VGG [35], ResNet [12], ResNeXt [44], DenseNet [15]
  • Convolution with stride of two followed by a maxpooling with stride of two are utilized to reduce the size of the feature maps to one fourth
  • Go deeper while maintaining high resolution feature maps
  • ReSidual U-block (RSU), which is able to extract intra-stage multi-scale features 
  • Multi-scale feature extraction - A 3 × 3 filter is good for extracting local features at each layer
  • Convolution + Feature Extraction + Downsample + Upsample

  • multi-scale feature extraction target at designing new modules for extracting both local and global information from features obtained by backbone networks.

RSU mainly consists of three component (ReSidual Ublock, RSU)

  • an input convolution layer, which transforms the input feature map
  • a U-Net like symmetric encoder-decoder structure which takes the intermediate feature map as input and learns to extract and encode the multi-scale contextual information
  • a residual connection which fuses local features and the multi-scale features

Dataset - Link

  • Labelled Images Samples
  • Ground Truth / Training Images
  • After 600k iterations (with a batch size of 12), the training loss converges and the whole training process takes about 120 hours Sample data


Creating this is also the key

Usecases

  • Remove background
  • Create portrait view

Paper #2 - BASNet: Boundary-Aware Salient Object Detection

Code - Link

Background removal tool - Link

Notes

  • Architecture is composed of a densely supervised Encoder-Decoder network and a residual refinement module
  • Hybrid loss - Binary Cross Entropy (BCE), Structural SIMilarity (SSIM) and Intersectionover-Union (IoU) losses.
  • Code Link
  • It assembles a UNet-like [57] deeply supervised [31, 67] Encoder-Decoder network with a novel residual refinement module

Paper #3 - BiSeNet: Bilateral Segmentation Network for Real-time Semantic Segmentation

Notes

  • Spatial Path with a small stride to preserve the spatial information and generate high-resolution features
  • Context Path with a fast downsampling strategy is employed to obtain sufficient receptive field
  • Spatial Path (SP) and Context Path (CP)


Paper #4 - BiSeNet V2: Bilateral Network with Guided Aggregation for Real-time Semantic Segmentation

Notes

This architecture involves: (i) a Detail Branch, with wide channels and shallow layers to capture low-level details and generate high-resolution feature representation; (ii) a Semantic Branch, with narrow channels and deep layers to obtain high-level semantic context

Keep Exploring!!!

January 20, 2022

Research Reads - Markdown pricing

Paper #1 - Markdowns in E-Commerce Fresh Retail: A Counterfactual Prediction and Multi-Period Optimization Approach

Key Notes

  • Due to the limited shelf life of perishable products and the limited opportunity of price changes, it is difficult to predict
  • sales of a product at a counterfactual price, and therefore it is hard to determine the optimal discount price to control inventory and to maximize future revenue.
  • Sequential pricing strategy by Markov decision process, and design a two-stage algorithm to solve it
  • Many perishable products, such as vegetables, meat, milk, eggs, bread, have a limited shelf life promotional markdown is a common approach for e-commerce fresh retails
  • The normal channel, where goods are sold by no-discount retail price
  • Markdown channel, where customers can buy goods by discount under the condition that their total purchase has reached a certain amount

Key Questions

  • First, can goods be sold out with the retail price before its expiry date?
  • Second, if not, what is the optimal discount price for promotional markdown to ensure the goods being sold out while maximizing the profit?
  • The first problem is about sales forecasting 
  • Second problem is about price-demand curve fitting
  • We observe the sales of a product with price A and B, we aim to predict the sales of a product with price C, which is counterfactual

  • To avoid price discrimination, the discounts of the same product in different stores within the same region should be all equal
  • To optimize the discount price, we need to take all stores in a region into consideration
  • We collect a set of observable covariate features 𝒙𝑖 ∈ R, including categories, holidays, event information, inherent properties and historical sales of products and shops
  • The key of pricing decision making is to accurately predict the demand of products at different discount prices
  • We aggregate data of all products by using the category information and learn the causal effect of each product jointly
  • The price elasticity is daily updated once the new transaction data is collected

Paper #2 - Markdown Pricing Under Unknown Demand

  • Unimodal Multi-Armed Bandit problem where the goal is to find the optimal price under an unknown unimodal reward function
  • “optimal” solutions exist under numerous variations on (a) the set of demand functions allowed, on (b) how inventory is treated, and on (c) the frequency at which prices are allowed to change, just to name a few. 
  • A Markdown Policy and Performance Guarantee: We introduce a policy which satisfies the markdown constraint
  • Optimality via a Minimax Lower Bound: We prove that our policy is in fact orderoptimal by showing

Paper #3 - Markdown Pricing Under Unknown Parametric Demand Models

  • Markdown Policies with Theoretical Guarantees
  • Tight Minimax Lower Bound
  • Impact of Smoothness
  • In the Discrete Multi-armed Bandit problem, the player is o↵ered a finite set of arms, with each arm providing a random revenue from an unknown probability distribution specific to that arm. The objective of the player is to maximize the total revenue earned by pulling a sequence of arms 

Keep Exploring!!!

January 09, 2022

Anamoly Detection

Paper #1 - A review on outlier/anomaly detection in time series data

Key Notes

  • An observation which deviates so much from other observations as to arouse suspicions that it was generated by a different mechanism


  • (Univariate time series) A univariate time series X = {xt }t ∈T is an ordered set of real-valued observations, where each observation is recorded at a specific time
  • (Multivariate time series) A multivariate time series X = {xt }t ∈T is defined as an ordered set of kdimensional vectors, each of which is recorded at a specific time

Outliers Type

  • Point outliers. A point outlier is a datum that behaves unusually in a specific time instant 
  • Subsequence outliers. This term refers to consecutive points in time whose joint behavior is unusual, although each observation individually is not necessarily a point outlier






  • multivariate time series is composed of more than one time-dependent variable a univariate analysis can be performed for each variable to detect univariate point outliers




Paper #2 - A Survey on GANs for Anomaly Detection

Notes

  • GANs are a framework for the estimation of generative models via an adversarial process in which two models, a discriminator D and a generator G, are trained simultaneously
  • The generator G aim is to capture the data distribution, while the discriminator D estimates the probability that a sample came from the training data rather than G



Paper #3 - Anomaly Detection of Time Series with Smoothness-Inducing Sequential Variational Auto-Encoder

Notes

  • time series anomaly detection can be in general divided into two settings: 
  • i) subsequence or whole sequence level anomaly whereby a subsequence xm,t1:t2 is labeled as an anomaly; 
  • ii) point level anomaly for which a measurement xm,t at time t in sequence m is treated as an anomaly. 


Note - Overview of GAN Structure

Notes

  • The generator learns to generate plausible data. The generated instances become negative training examples for the discriminator.
  • The discriminator learns to distinguish the generator's fake data from real data. The discriminator penalizes the generator for producing implausible results.

More Reads

Keep Exploring!!!

Fraud Detection Research Papers

Fraud Detection Research Papers

Paper #1 - Credit Card Fraud Detection in e-Commerce: An Outlier Detection Approach

Notes

  • No prior knowledge of outliers or inliers is needed
  • The proposed algorithm is easy to scale as it can easily be implemented in a distributed manner
  • Proposed algorithm is general in nature and does not require k-means algorithm as the only base clustering algorithm. 
  • Can estimate a measure of consistent behavior (good behavior) for each data point then we can identify outliers as data points with low consistency score.
  • Attempt the problem of outlier detection by estimating a consistency score
  • In our experiments we found that incrementally increasing k with a xed step works just as well as the ensemble created by carefully selecting k using a principled approach such as Silhouette Score
  • For #Fraud #detection with limited dataset, Algorithms to get started to find potential transactions #IsolationForecast, #OneClassSVM, #Clusteringbasedoutlierdetection

Paper #2 - A Comparison Study of Credit Card Fraud Detection: Supervised versus Unsupervised

Notes

  • 6 supervised classification models, i.e., Logistic Regression (LR), K-Nearest Neighbors (KNN), Support Vector Machines (SVM), Decision Tree (DT), Random Forest (RF), Extreme Gradient Boosting (XGB)
  • 4 unsupervised anomaly detection models, i.e., One-Class SVM (OCSVM), Auto-Encoder (AE), Restricted Boltzmann Machine (RBM), and Generative Adversarial Networks (GAN)
  • Supervised Learning Methods
  • Logistic regression allows us to estimate the probability of a categorical response based on one or more predictor variables x.
  • KNN algorithm essentially boils down to forming a majority vote between the K most similar instances to a given unseen observation
  • SVM is to derive an optimal hyperplane that maximizes the margin between two classes
  • Decision trees are simple but intuitive models that utilize a top-down approach in which the root node creates binary splits until a certain criteria is met
  • XGB uses gradient descent for optimization to improve the predictive accuracy at each optimization step by following the negative of the gradient as we are trying to find the sink in a n-dimensional plane

Unsupervised Learning Methods

  • OneclassSVM - The algorithm learns a soft boundary in order to embrace the normal data instances using the training set, and then, using the testing instance, it tunes itself to identify the abnormalities that fall outside the learned region
  • RBM model consists of visible and hidden layers, which are connected through symmetric weights. The objective of the generative training in RBM is to learn the unknown (h) iteratively using the input (x).
  • An auto-encoder (AE) learns to map from input to output through a pair of encoding and decoding phases
  • GAN AnoGAN by simultaneously learn an encoder E that maps input samples x to a latent representation z, along with a generator G and discriminator D during training.

Paper #3 - xFraud: Explainable Fraud Transaction Detection

Key Notes

  • Fraudster user detection
  • Fraud transaction detection
  • Methods that do not need to define meta-paths a priori, instead are able to automatically learn these patterns using a GNN.

  • xFraud detector. We are inspired by Transformer [39] and HGT [18], when designing the xFraud detector incl. heterogeneous mutual attention and heterogeneous message passing with key, value, and query vector operations (self-attention mechanism).

Paper #4 - TitAnt: Online Real-time Transaction Fraud Detection in Ant Financial

Key Notes

  • Rule-based methods have been extensively studied over the years [46] for fraud detection problem
  • several unsupervised learning and anomaly detection methods are introduced
  • Recurrent neural network to exploit temporal information of account behavior
  • Anomaly detection methods, such as isolation forest sheds light on fraud detection tasks



Paper #5 - A Comprehensive Survey on Machine Learning Techniques and User Authentication Approaches for Credit Card Fraud Detection

Key Notes

  • Combination of Hidden Markov Model (HMM) and K-Means algorithms was used in (Kumari and Choubey, 2017) to identify the fraudulent activities on credit cards
  • A transaction is considered suspicious if its distance to the center of the cluster exceeds a pre-set threshold
  • Self-Organizing Map (SOM) is an unsupervised neural network learning model, which has been used to form customer profiles and visualize fraudulent patterns

Paper #6 - A Survey of Credit Card Fraud Detection Techniques: Data and Technique Oriented Perspective

Key Notes

  • A Hidden Markov Model is a double embedded stochastic process which is applied to model much more complicated stochastic processes as compared to a traditional Markov model
  • Genetic algorithms have been used in data mining tasks mainly for feature selection. 
  • A Bayesian network is a graphical model that represents conditional dependencies among random variables. The underlying graphical model is in the form of directed acyclic graph


More Reads

Keep Exploring!!!

June 14, 2021

Quick Research Paper Reads - Retail - Supply Chain

Price Optimization in Fashion E-commerce

Key Notes

  • Key parameters - product display page, MRP and the discounted price, clickthrough rate (CTR) & conversion
  • To maximize revenue, we need to predict the quantity sold of all products at any given price
  • Another significant challenge is cannibalization among products
  • We overcame this problem by running the model at a category level and creating features at a brand level, which can take into account cannibalization
  • To solve it, the Linear Programming optimization technique


Feature Engineering

    
Linear Programming
Now we need to choose one of these three prices such that the net revenue is maximized.

Online Data Sources
  • Clickstream data: this contained all user activity such as clicks, carts, orders, etc.
  • Product Catalog: this contained details of a product like brand, color, price, and other attributes related to the product.
  • Price data: this contained the price and the quantity sold of a product at hour level granularity.
  • Sort Rank: this contained search rank and the corresponding scores for all the live products on the platform
Key Notes
  • The task of assortment planning is to determine the optimal subset of k products to be stocked in each store so that the assortment is localized to the preferences of the customers shopping in that store.
  • Broadly there are three aspects to assortment planning, (1) the choice of the demand model, (2) estimating the parameters of the chosen demand model and (3) using the demand estimates in
  • an assortment optimization setup.
  • The forecast demand will then be used in a suitable stochastic optimization algorithm to do the assortment planning.
In the age based model for demand forecasting of fashion items, the demand of an article i in store s at time t, is formulated as:

February 24, 2021

Deep Learning Healthcare Applications - Research Paper reads

Paper #1 - System for Recommending Facial Skincare Products

Key Notes

  • Multi-feature processing and classification of skin quality and acne status

Approach

  • K-means cluster to search for acne
  • Binary threshold using an adaptive method
  • Identified the location of acne and provided recommendations to consumers
  • A scale of oiliness was produced by labeling images of the weighted average

Steps

  • The first feature used to determine whether the skin is oily
  • Acne detection
  • The brightness image is subtracted from the normalized grayscale image

Paper #2 - A Computer Vision Application for Assessing Facial Acne Severity from Selfie Images

Keynotes

  • Acne is the 8th most common skin disorder in the world
  • Transfer learning approach by extracting image features using a ResNet 152 pre-trained model, then adding and training a fully connected layer to learn the target severity level from labeled images.
  • Mobile application for acne assessment
  • Extracted skin patches from facial skins
  • Haar feature-based cascade classifier
  • Eye location, we inferred the regions of the forehead, cheeks and chin skin patches

Paper #3 - Deep Learning Methods for Selecting Appropriate Cosmetic Products for Various Skin Types: A Survey

Key Notes

  • The cosmetic data from various websites @cosme and @Nykaa gathered for this model evaluation.
  • The cosmetic product composition will be given based on skin types; dry, natural or oily.

Paper #4 Deep Learning Algorithms for Recognition of Facial Ageing Features

Keynotes

  • Wrinkles, Dark spots, Under-eye circles
  • Face Detection, wrinkle detection, scoring
  • Facial zone - ensemble of regression trees, retrained for 50 fiducial points (dlib implementation) + contours detection
  • Alignment - affine transformation
  • Wrinkles area detection - cut areas by support points

More Reads


Key Notes
  • Spectral Residual (SR) - Approach based on Fast Fourier Transform (FFT). Key Steps are
  • (1) Fourier Transform to get the log amplitude spectrum; 
  • (2) calculation of spectral residual; and 
  • (3) Inverse Fourier Transform that transforms the sequence back to the spatial domain

Visual saliency detection domain. Applying CNN on the basis of SR output directly
CNN as our discriminative model architecture

More Reads

Happy Learning!!!

January 10, 2021

Tracking @ 2021 - Paper Reads - Object Tracking

Paper - Object Detection and Tracking Algorithms for Vehicle Counting: A Comparative Analysis

Key Notes

  • Models used - CenterNet and Deep SORT, Detectron2 and Deep
  • SORT, and YOLOv4 and Deep SORT
  • YOLO and SORT algorithms
  • Counting Techniques
  • Counting by frame differencing
  • Counting by detection
  • Motion based counting
  • Deep learning based counting

OBJECT DETECTORS

CenterNet

  • CenterNet functions on the intuition that if a detected bounding box has a higher Intersection over Union (IoU) with the ground-truth box
  • CenterNet is a singlestage detector 

Detectron2

Detectron2 supports implementation to multiple object detection algorithms using different backbone network architectures such as ResNET {50, 101, 152}, FPN, VGG16

YOLOv4

You Only Look Once (YOLO) is the state-of-the-art object detection algorithm. New techniques adopted in YOLOv4 are: (i) WeightedResidual-Connections, (ii) Cross-Stage-Partial-Connections, (iii) Cross mini-batch, (iv) Normalization (CmBN), (v) Selfadversial-training, (vi) Mish-activation

EfficientDet

Follows single-stage detectors pattern

SORT

Simple Online and Realtime Tracking (SORT) is an implementation of tracking-by-detection framework where the main objective is to detect objects each frame and associate them for online and real-time tracking application

Deep SORT

A combination of Kalman Filter and Hungarian algorithm is used for tracking

Paper - Tracking Objects as Points

Key Notes

  • We track objects by tracking their centers. We learn a 2D offset between two adjacent frames and associate them based on center distance.
  • A simple displacement prediction, akin to sparse optical flow, allows objects in different frames to be linked
  • Joint detection and tracking
  • Early approaches [2, 47] used Kalman filters to model object velocities

Paper - SMOT: Single-Shot Multi Object Tracking

Key Notes

  • The first stage exercises a per-frame object detector to localize object bounding boxes in each frame
  • The second stage, tracklet generation, merges detection results to create a set of tracklets, i.e., short tracks, based on short-term cues

More Read

FairMOT: On the Fairness of Detection and Re-Identification in Multiple Object Tracking

Object Detection and Tracking in 2020


Paper - ByteTrack: Multi-Object Tracking

Key Notes

In this paper, we identify that the similarity with tracklets provides a strong cue to distinguish the objects and background in low score detection boxes

Data association is the core of multi-object tracking, which first computes the similarity between tracklets and detection boxes and then matches them according to the similarity.

Location and motion similarity are accurate in the short-range matching.

Code

Codes

Happy Learning!!!

December 27, 2020

Mental Health & AI - Research paper reads

Paper #1 - Forecasting the onset and course of mental illness with Twitter data

Key Notes

  • Dataset - 204 individuals (105 depressed, 99 healthy).
  • Models - Classify depressed and healthy content, supervised learning algorithms, time series model
  • Depression­ related terms such as diagnosis, antidepressants, psychotherapy, and hospitalization


Paper #2 - Predicting User Emotional Tone in Mental Disorder Online Communities


Paper #3 - Mental Health and Sensing

Features

  1. Facial expression
  2. Heart rate variability
  3. Eye movement
  4. Electrodermal activity
  5. Mobility and location
  6. Speech patterns
  7. Technology use
  8. Activity
  9. Social interaction
  10. Communication patterns
  11. Social media



More Reads

Big Data Analytics and AI in Mental Healthcare

What are We Depressed about When We Talk about COVID19: Mental Health Analysis on Tweets Using Natural Language Processing

Temporal Mental Health Dynamics on Social Media

Personal Mental Health Navigator: Harnessing the Power of Data, Personal Models, and Health Cybernetics to Promote Psychological Well-being

Keep Thinking!!!