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I am an Assistant Professor at the School Business at Stevens Institute of Technology. My research focuses on large-scale Reputation Systems, as well as on scalable Data Mining and Machine Learning algorithms for Business Analytics.

Before joining Stevens, I was a post-doctoral researcher and member of the Data Management Lab at the Computer Science Department at Boston University, working with Prof. Evimaria Terzi. While at BU, I held the position of Visiting Fellow at the Rafik B. Hariri Institute for Computing and Computational Science & Engineering.

I received my PhD from the Dept. of Computer and Science Engineering at the University of California, Riverside (UCR), with a specialization in Data Mining and Social Media. While in UCR, I was a member of the Database Lab, working with Prof. Dimitrios Gunopulos and Prof. Vassilis Tsotras. The title of my thesis is “Algorithmic Challenges in Social Media Search”. I received my Bachelor’s in Informatics from the Athens University of Economics and Business, with a specialization in Information Systems.

Latest News.

April 13, 2018:
Happy to be on the program committee of the 5th IEEE International Conference on Data Science and Advanced Analytics (DSAA), to be held October 1-4 2018 in Turin, Italy.

April 4, 2018:
New Affiliation: Stevens Institute for Artificial Intelligence

March 16, 2018:
New research collaboration with Jefferies

January 30, 2018:
Our paper Unsupervised Tip-Mining from Customer Reviews has been accepted to Decision Support Systems.

June 22, 2017:
Happy to be on the program committee of KDD-18, to be held August 19-23 2018 in London, UK.

July 1, 2017:
Our paper Economic Impact and Policy Implications from Urban Shared Transportation: The Case of Pittsburgh’s Shared Bike System has received a minor revision from PLoS One.

June 22, 2017:
Happy to be on the program committee of WWW-18, to be held April 23–27 in Lyon, France.

Journal Publications.

Di Zhu, Theodoros Lappas, and Julie Zhang
Unsupervised Tip-Mining from Customer Reviews
Decision Support Systems

Konstantinos Pelechrinis, Christos Zacharias, Marios Kokkodis, Theodoros Lappas
Economic Impact and Policy Implications from Urban Shared Transportation:
The Case of Pittsburgh’s Shared Bike System

PLoS One

Apostolos Filippas, Theodoros Lappas
Strength in Numbers: Using Big Data to Simplify Sentiment Classifi cation
Big Data

Georgios ValkanaFs, Theodoros Lappas, and Dimitrios Gunopulos
Mining Competitors from Large Unstructured Datasets
IEEE Transactions on Knowledge and Data Engineering

Theodoros Lappas, Gaurav Sabnis, and Georgios Valkanas
The Impact of Fake Reviews on Online Visibility:
A Vulnerability Assessment of the Hotel Industry.

Information Systems Research

* Runner Up for best ISR paper in 2016.

Video Summary

NBC New York

NBC Bay Area

INFORMS Journal Highlights,  November 2016

Article @Stevens News

Serhan Kotiloglu, Theodoros Lappas , Kostantinos Pelechrinis, Panagiotis Repoussis
Personalized multi-period tour recommendations
Tourism Management.

Ke Zhang, Theodoros Lappas , Kostantinos Pelechrinis
Effects of Promotions on Location-Based Social Media: Evidence from Foursquare
International Journal of Electronic Commerce.

Post Gazzette

Pitt News

Wesa FM

Pei Yang, Hongxia Yang, Haoda Fu, Dawei Zhou, Jieping Ye, Theodoros Lappas, and Jingrui He
Jointly Modeling Label and Feature Heterogeneity in Medical Informatics
ACM Transactions on Knowledge Discovery from Data, 2015

Dimitrios Kotzias, Theodoros Lappas, Dimitrios Gunopulos
Home is Where your Friends Are:
Utilizing the Social Graph to Locate Twitter Users in a City.

Elsevier’s Information Systems, 2015.


  • Fall 2013: Data and Knowledge Management (2 sections, Grad)

  • Spring 2014: Data and Knowledge Management (2 sections, Grad), Web Mining (1 section, Grad)

  • Fall 2014: Web Mining (3 sections, Grad)

  • Spring 2015: Web Mining (2 sections, Grad), Relational Databases (1 section, Undergrad)

  • Fall 2015: Web Mining (2 sections, Grad)

  • Spring 2016: Web Mining (2 sections: 1 Grad, 1 Corporate at Pfizer )

  • Fall 2016: Web Mining (4 sections, Grad: 3 on-campus and 1 online)

  • Spring 2017: Web Mining (3 sections, Grad: 2 on-campus and 1 Corporate at Verizon )


A framework for tracking the spatiotemporal burstiness of Terms
Get the Code

As described in the following publications:

Theodoros LappasMarcos VieiraDimitrios Gunopulos and Vassilis Tsotras
STEM: A SpatioTemporal Miner for Bursty Activity – SIGMOD 2013 (Demo)

Theodoros LappasMarcos VieiraDimitrios Gunopulos and Vassilis Tsotras
On the Spatiotemporal Burstiness of Terms – VLDB 2012 
Download Slides Bibtex



Theodoros Lappas
Assistant Professor of Information Systems
School of Business, Stevens Institute of Technology
1 Castle Point Terrace
Hoboken, NJ 07030
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