Foundations + Research

Xiaojing Yangfrom foundations to applied systems

A bilingual knowledge base on mathematics, statistics, machine learning, NLP, LLMs, model evaluation, and applied AI research. The goal is simple: make the foundations reusable, then connect them to real experiments.

Foundations

The concepts I want to keep sharp

This track is where existing high-quality resources become my own explanations, notes, examples, and interview-ready mental models.

Mathematics

Linear algebra, calculus, optimization, graphs, and representation spaces explained through ML and NLP examples.

Statistics

Probability, distributions, confidence intervals, bootstrap testing, hypothesis tests, and uncertainty in evaluation.

Machine Learning

Splits, generalization, model selection, cross-validation, losses, regularization, and practical training workflows.

NLP & LLMs

Tokenization, embeddings, Transformers, fine-tuning, prompting, sequence models, and language-specific evaluation.

Research Engineering

Experiment repositories, config-driven pipelines, logging, annotation sheets, demos, and reproducible analysis.

Research & Applications

Broad enough for future work, concrete enough for real projects

This track avoids boxing the blog into one thesis topic. It groups research by capability: building, evaluating, explaining, retrieving, and applying AI systems.

Multilingual AI

Machine translation, multilingual NLP, low-resource adaptation, terminology, domain adaptation, and language variation.

Model Evaluation

Metrics, benchmark design, statistical testing, ablations, error analysis, human evaluation, and robustness.

Explainability & Responsible AI

Interpretability, bias analysis, attribution, model auditing, SHAP/LIME, Shapley values, and controlled evaluation.

Retrieval & Knowledge Systems

Information retrieval, RAG, long documents, graph retrieval, evidence grounding, and document intelligence.

Applied ML Systems

Data pipelines, classification, forecasting, information extraction, deployment, product demos, and applied analytics.

Latest notes

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Posts may be in English, Chinese, or bilingual. Foundations posts often start from strong public resources; research posts connect those foundations to my own experiments.

Research & ApplicationsMultilingual AIEN

Why LoRA Fits Low-Resource Domain Adaptation

A research-facing explanation of why LoRA is a good fit for low-resource domain machine translation: controlled adaptation, lower experimental cost, and reduced overfitting risk.

Research & ApplicationsMultilingual AI中文

LoRA 领域适配中的数据规模实验

如何研究领域数据规模对 LoRA 机器翻译适配的影响:数据多少才够,什么时候收益递减,什么时候是数据质量问题。

This blog complements my portfolio.

Portfolio pages show what I built. These notes explain the foundations, decisions, experiments, and tradeoffs behind the work.