yatawara.com / research

Research

A single research program along four pillars that share one core: modeling complex temporal and spatial patterns — how systems encode, persist, and forget information — to produce actionable insight.

01

Financial Volatility & Time-Series Econometrics

// primary

How do markets remember? My primary line of work develops new econometric models for volatility persistence — measuring the shape of market memory directly from data instead of assuming it. The central finding: that memory decays sub-exponentially — fast at first, then a long, faint tail.

$ kernel --plot stretched-exponential --alpha 0.27 --live

The Shape of Volatility Memory In progress

Volatility memory kernels across 100+ assets — equities, FX, commodities, fixed income, crypto, and the VIX — follow sub-exponential (stretched-exponential) decay, fitting markedly better than GARCH and FIGARCH. Introduces the GMARCH and SEARCH modeling frameworks.

In production — target: Journal of Business & Economic Statistics

MF2V-GARCH In progress

Augments Conrad & Engle's (2025) Multiplicative Factor Multi-Frequency GARCH with smoothed trading volume. Evaluated on 15 US assets with rolling out-of-sample forecasts; ships with a MATLAB toolbox.

Target: Journal of Forecasting

MF2-GARCH-A In progress

A sign-sensitive long-run component, giving the long-run variance an asymmetric response to positive versus negative shocks — bad news and good news leave different marks on market memory.

Target: International Journal of Forecasting

MF2-EGARCH In progress

An exponential-GARCH version of the multiplicative-factor multi-frequency framework, including asymmetric MEM and logarithmic MEM long-term variants.

Target: International Journal of Forecasting

Additional volatility models

MR-HYGARCH FI-GJRGARCH ST-FI-GJRGARCH

Multiple Regime Hyperbolic GARCH (MR-HYGARCH), Fractionally Integrated GJR-GARCH (FI-GJRGARCH), and Smooth-Transition FI-GJRGARCH — extending long-memory and asymmetric volatility modeling.

Software

MF2V-GARCH Toolbox for MATLAB — open-source implementation of the multiplicative-factor multi-frequency framework with smoothed trading volume.

View on GitHub ↗
02

Hybrid Time Series & Machine Learning

// forecasting

Explainable machine-learning forecasting, grounded in statistics — pairing the structure of classical time-series models with the flexibility of deep learning, without giving up interpretability.

Hybrid LSTM for Influenza Forecasting In progress

A hybrid LSTM architecture with Yeo-Johnson scaling for forecasting influenza-like illness — combining recurrent memory and convolutional feature extraction for more accurate, explainable public-health forecasts.

Presented at JSM 2025 · with student Noah Gallego and Prof. Isuru Ratnayake (KUMC) · manuscript in preparation

03

Environmental Justice & Air Quality

// spatial

Statistical frameworks for measuring who breathes what — quantifying multi-pollutant exposure, its fine-scale spatial structure, and how it tracks with income across communities.

Income-Based Exposure Disparities in California Published

A county-level, multi-pollutant framework (PM2.5, NO₂, O₃, SO₂, CO) quantifying income-based air-quality disparities across California.

Environmental Research: Health, 2025 · with students Kayla Ko & Christian Rodriguez · CES Mini-Grant

Fine-Scale Air-Quality Heterogeneity in Twin Cities Published

Evaluating fine-scale air-quality heterogeneity using a network of 45 low-cost multi-pollutant sensors across Minneapolis–St. Paul.

ACS ES&T Air, 2025

Air Pollution & Fertility Patterns Ongoing

An ongoing study of the relationship between air pollution and fertility patterns across California counties.

CV Pathway 2025 apprenticeship

04

AI in Statistics Education

// elevate

Building and studying AI-powered tools that help students learn statistics — turning large language models from answer generators into thinking partners. Supported by the California Learning Lab ELEVATE grant.

Scaffolded LLM Tutors

Lead author. "From Answer Generators to Thinking Partners" — a Custom GPT framework for tutoring, prompting, and ethics in statistics education.

Submitted to JSDSE

Structured AI Tutoring in Engineering Education Published

Co-author. A work-in-progress study of structured AI tutoring in engineering education.

IEEE FIE 2025

Computer-Aided Instruction for K–12 Teachers Published

A cognitive-apprenticeship approach to integrating large language models into instruction for K–12 teachers.

IEEE FIE 2025


05

Collaborators

// network
V.A. Samaranayake · Missouri S&T (PhD advisor) Isuru Ratnayake · KUMC Alberto Cruz · CSUB ECE (ELEVATE PI) Jianjun Wang · CSUB Math Maruti Mishra · CSUB Eduardo Montoya · CSUB Math Bilin Zeng · CSUB Math
06

Grants & Funding

// funded
Year Project Role Source
2025 Air Pollution Disparities in California 2000–2025 PI CES Mini-Grant, CSUB
2025–26 ELEVATE: Enhancing Learning Experiences Via AI Techniques Co-PI California Learning Lab AI FAST Challenge