Hegler is available for hire

Hegler Tissot

Verified Expert in Engineering

Database Developer

Location

Curitiba - State of Paraná, Brazil

Toptal Member Since

January 19, 2021

Hegler has over 30 years of computer science and commercial application-systems development experience, mainly focused on designing large transactional and analytical database projects over different industry sectors, including healthcare, telecom, manufacturing, quality control, and transport logistics. More recently, Hegler has focused on applying knowledge-embedding representation to build predictive models from structured and unstructured data.

Data Reporting Data Engineering Data Modeling Oracle Performance Tuning Debugging Data Mining Data Warehouse Design Data Analysis Data Migration Data Scientist Database Design SQL Oracle PL/SQL Relational Databases Databases

Portfolio

Drexel University

Databases, Database Design, PostgreSQL, Systems Analysis

University of Pennsylvania

Databases, Python, Machine Learning, Natural Language Processing (NLP)...

University College London

GPT, Natural Language Processing (NLP)...

Experience

Database Modeling - 20 years SQL - 20 years Oracle PL/SQL - 20 years Database Design - 20 years Oracle Database - 20 years Data Mining - 15 years Data Warehouse Design - 15 years Text Mining - 6 years

Availability

Part-time

Preferred Environment

Risk Models, Predictive Learning, Predictive Modeling, Ontology Framework, Text Mining, Data Mining, Knowledge Bases, Database Modeling, PostgreSQL, Oracle

The most amazing...

...project I've worked on in healthcare is performing risk assessments of miscarriage during pregnancy, providing evidence to support case-based explainability.

Work Experience

Assistant Teaching Professor

2021 - PRESENT

Drexel University

Taught basic to advanced database-related courses to undergrad and graduate students.
Supervised senior research projects involving machine learning applications in the database context.
Worked on machine learning research topics, including extracting explainability from data, generating synthetic data, and designing unsupervised and semi-supervised ML modules.

Technologies: Databases, Database Design, PostgreSQL, Systems Analysis

Senior Postdoctoral Research Engineer

2019 - 2021

University of Pennsylvania

Provided guidance to other researchers regarding system and services engineering.
Developed demos to expose the resulting research work.
Developed a risk assessment framework combining knowledge graphs, embedding representation, and machine learning focused on the clinical domain.

Technologies: Databases, Python, Machine Learning, Natural Language Processing (NLP), GPT, Generative Pre-trained Transformers (GPT), APIs

Senior Research Fellow

2017 - 2019

University College London

Applied research in health informatics focused on the development of a text mining pipeline to mimic and evaluate semi-automatic patient recruitment for clinical trials.
Researched the application of representation models for knowledge graph embedding in clinical risk assessment tasks.
Gained teaching experience in database modeling and knowledge embedding representation.
Supervised the master's students in order to guide them through their final research work.

Technologies: Natural Language Processing (NLP), GPT, Generative Pre-trained Transformers (GPT), Elasticsearch, Databases, Java

Postdoctoral Research Fellow

2017 - 2017

Macquarie University

Developed an information extraction system able to reason about temporal implication rules from large knowledge bases.
Co-supervised master's students and followed up their research.
Performed the first designing experiments regarding the representation learning of knowledge graph embedding.

Technologies: Information Extraction, Temporal Reasoning, GPT, Natural Language Processing (NLP), Generative Pre-trained Transformers (GPT)

Senior Database Analyst

2011 - 2016

Public Healthcare System

Performed the Oracle database modeling and consulting in the healthcare industry.
Designed and deployed data integration and monitoring systems used to share data among 75 Oracle database servers and manipulate over one million medical records.
Delivered Oracle database training (SQL and tuning) to other members of the group.

Technologies: Data Reporting, SQL, Database Modeling

Senior Database Analyst

2009 - 2010

Suntech

Designed databases used by the largest telecommunications industry company in Brazil, including business intelligence tools, ETL procedures, CDR/SMS processing, and KPI monitoring systems.
Architected, tuned, and coded database functions and ETL processes to build DW for telecom network KPIs.
Delivered Oracle database training to other group members, covering design, SQL, PL/SQL, and tuning.

Technologies: ETL, Key Performance Indicators (KPIs), Data Warehouse Design, Oracle Database

Senior Technical Leader

2002 - 2009

HALTSO

Managed a team of up to seven coworkers in charge of providing information system and ORACLE database consulting and more than 20 customers.
Supervised and led the overall design of SaaS systems for specific customers.
Provided Oracle database training and consulting services to multiple clients.

Technologies: Oracle PL/SQL, SQL, Data Warehouse Design, Database Design

Experience

Healthcare Data Integration

I designed and deployed data integration and monitoring systems used to selectively share data among more than 70 database servers used to manipulate over one million medical records in the public health system.

DataDecision

A Java web-based interface for accessing and querying data warehouse systems. Restricted to Oracle database repositories, the system's features included query log management, preference savings, and data access control. The project is now deprecated.

Knowledge Embedding Representation (KER)

https://github.com/hextrato/KER/

This research project was developed to learn entity and relationship embedding representation for knowledge graphs focused on domain-specific tasks. Clinical risk assessment based on patient records is one of its applications.

Risk Assessment and Prediction Explainability

My key project in the health industry is about performing a risk assessment of miscarriage in early pregnancy stages, providing evidence about how features are correlated to the risk labels to support case-based explainability. For example: “Why do two pregnant women at the same age have distinct miscarriage risks? Lower risk due to use of folic acid and higher risk due to smoker status”. Models are generic and can be applied across multiple domains.

Skills

Languages

SQL, Stored Procedure, Python, JavaScript, PL/pgSQL, Java

Tools

Oracle SQL Data Modeler, Microsoft Excel, Microsoft Access, AutoML

Paradigms

Database Design, Database Development, Business Intelligence (BI), HIPAA Compliance, Qualitative Research, ETL, ETL Implementation & Design, OLAP, Data Science

Platforms

Oracle Database, Oracle, Docker, Amazon Web Services (AWS), Google Cloud Platform (GCP)

Storage

PostgreSQL, Database Modeling, Oracle PL/SQL, Data Integration, Relational Databases, Databases, Oracle 12c, PL/SQL, PL/SQL Developer, Database Architecture, DB, Database Administration (DBA), Data Pipelines, Oracle Database Tuning, JSON, SQL Loader, Elasticsearch, MySQL, NoSQL

Industry Expertise

Healthcare

Other

Data Mining, Systems Analysis, Data Warehouse Design, Data Analysis, Data Reporting, Indexing, Data Engineering, CSV File Processing, Data Architecture, Data Modeling, Consulting, Data Migration, Query Optimization, Reporting, Oracle Performance Tuning, Healthcare & Insurance, Database Optimization, CSV, Data Manipulation, Database Schema Design, Debugging, Logical Database Design, Partitioning, Datasets, Data Scientist, Warehouses, Text Mining, Predictive Modeling, Natural Language Processing (NLP), Ontologies, Temporal Reasoning, Information Extraction, Key Performance Indicators (KPIs), Cluster Analysis, Risk Assessment, Data Cleaning, Data Cleansing, ETL Development, PL/SQL Tuning, Performance Tuning, Data Warehousing, Knowledge Graphs, Clustering, Dimensionality Reduction, Data Analytics, Integration, Artificial Intelligence (AI), GPT, Generative Pre-trained Transformers (GPT), Knowledge Bases, Predictive Learning, Risk Models, Machine Learning, Dashboards, APIs, Data-driven Dashboards, Customer Relationship Management (CRM), Amazon RDS, RESTful Microservices

Libraries/APIs

NumPy, REST APIs, Pandas, Scikit-learn

Frameworks

Ontology Framework

Education

2012 - 2016

Doctoral Degree in Computer Science

Federal University of Parana (UFPR); University of Sheffield - Curitiba, Brazil; Sheffield, UK

2002 - 2004

Master's Degree in Computer Science

Federal University of Santa Catarina (UFSC) - Florianopolis, Brazil

1990 - 1993

Bachelor's Degree in Computer Science

Federal University of Parana (UFPR) - Curitiba, Brazil

Certifications

NOVEMBER 1997 - PRESENT

Oracle Database Application Tuning

Fontoura

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