Maheswaran, Rajiv


Spatiotemporal Patterns in Social Networks

AAAI Conferences

Social media generated by location-services-enabled cellular devices produce enormous amounts of location-based content. Spatiotemporal analysis of such data facilitate new ways of modeling human behavior and mobility patterns. In this paper, we use over 10 millions geo-tagged tweets from the city of Los Angeles as observations of human movement and apply them to understand the relationships of geographical regions, neighborhoods and gang territories. Using a graph based-representation of street gang territories as vertices and interactions between them as edges, we train a machine learning classifier to tell apart rival and non-rival links. We correctly identify 89% of the true rivalry network, which beats a standard baseline by about 30%. Looking at larger neighborhoods, we were able to show that the direction of displacement, i.e, the distribution of movement direction, can be used as a profile to identify physical (or geographic) barriers when it is not uniform. Finally, considering the temporal dimension of tweets, we detect events taking place around the city by identifying irregularities in tweeting patterns.


Adaptive Agent for Player-Specific Fitness and Health Incentives in Mobile Location Based Games

AAAI Conferences

As location-based mobile games become more popular, movement becomes an integral part of game play. This provides an opportunity for the game to influence player behavior in the real world, potentially inducing more physical activity (and better health) through intelligent adaptation of the game mechanic. We describe the application of Markov Decision Processes (MDPs) to model the player's behavior in a custom-built location-based zombie fighting game. The game agent uses this model - a user specific optimal policy (USOP) - to adjust the game behavior to encourage as much game play as possible. Our experiments with human subjects showed that game play time was indeed increased over the control condition. We look at how games can be used to model user behavior and then unobtrusively effect agent-determined behavioral change.


Security Games on Social Networks

AAAI Conferences

Many real-world problems exhibit competitive situations in which a defender (a defending agent, agency, or organization) has to address misinformation spread by its adversary, e.g., health organizations cope with vaccination-related misinformation provided by anti-vaccination groups. The rise of social networks has allowed misinformation to be easily and quickly diffused to a large community. Taking into account knowledge of its adversary’s actions, the defender has to seek efficient strategies to limit the influence of the spread of misinformation by the opponent. In this paper, we address this problem as a blocking influence maximization problem using a game-theoretic approach. Two players strategically select a number of seed nodes in the social network that could initiate their own influence propagation. While the adversary attempts to maximize its negative influence, the defender tries to minimize this influence. We represent the problem as a zero-sum game and apply the Double Oracle algorithm to solve the game in combination with various heuristics for oracle phases. Our experimental results reveal that by using the game theoretic approach, we are able to significantly reduce the negative influence in comparison to when the defender does not do anything. In addition, we propose using an approximation of the payoff matrix, making the algorithms scalable to large real-world networks.


TEAM-IT : Location-Based Gaming in Real and Virtual Environments

AAAI Conferences

Location-based games are an emerging paradigm fortraining, simulation, entertainment, health and many other domains. In this paper, we consider the role of artificialagents in such games. We also examine how human teams perform when given the same game, playedin both a real environment with mobile devices and alsoin a virtual environment that replicates the real environment.We perform the first direct comparison of real andvirtual instantiations of the same location-based game.We show the similarities and differences in game playand then investigate how adding an advice-giving agentchanges the experience.


Location-Based Game Platform for Behavioral Data Collection in Disaster Rescue Scenarios

AAAI Conferences

Location-based games are an emerging paradigm for training, simulation, entertainment, health and many other domains. In this paper, we consider the role of location-based games as a platform for data collection and analysis of human behavior. We also examine how human teams perform in a disaster scenario when such a scenario is mapped to a game environment conducted as a location-based augmented reality game. We use a pilot experiment to study human behavior between simulated disaster rescue teams and an integrated commander for the purpose of future research into improving exploitation of local tasks versus exploration of assigned objectives by disaster response teams. We show the results of our pilot experiment, analyze the effectiveness of this game as a data collection platform and then investigate how additional experiments may be conducted to formalize this problem further.


Adaptive Learning Agents for Sustainable Building Energy Management.

AAAI Conferences

Nearly 20% of total energy consumption in the United States is accounted for in heating, ventilation, and air conditioning (HVAC) systems. Smart sensing and adaptive energy management agents can greatly decrease the energy usage of HVAC systems in many building applications, for example by enabling the operator to shut off HVAC to unoccupied rooms. We implement a multimodal sensor agent that is nonintrusive and low-cost, combining information such as motion detection, CO2 reading, sound level, ambient light,and door state sensing. We show that in our live test bed at the USC campus, these sensor agents can be used to accurately estimate the number of occupants in each room using machine learning techniques, and that these techniques can also be applied to predict future occupancy by creating agent models of the occupants. These predictions will be used by control agents to enable the HVAC system increase its efficiency by continuously adapting to occupancy forecasts of each room.


Reports of the AAAI 2011 Spring Symposia

AI Magazine

The Association for the Advancement of Artificial Intelligence, in cooperation with Stanford University's Department of Computer Science, presented the 2011 Spring Symposium Series Monday through Wednesday, March 21–23, 2011 at Stanford University. The titles of the eight symposia were AI and Health Communication, Artificial Intelligence and Sustainable Design, AI for Business Agility, Computational Physiology, Help Me Help You: Bridging the Gaps in Human-Agent Collaboration, Logical Formalizations of Commonsense Reasoning, Multirobot Systems and Physical Data Structures, and Modeling Complex Adaptive Systems As If They Were Voting Processes.


Reports of the AAAI 2011 Spring Symposia

AI Magazine

The Association for the Advancement of Artificial Intelligence, in cooperation with Stanford University’s Department of Computer Science, presented the 2011 Spring Symposium Series Monday through Wednesday, March 21–23, 2011 at Stanford University. The titles of the eight symposia were AI and Health Communication, Artificial Intelligence and Sustainable Design, AI for Business Agility, Computational Physiology, Help Me Help You: Bridging the Gaps in Human-Agent Collaboration, Logical Formalizations of Commonsense Reasoning, Multirobot Systems and Physical Data Structures, and Modeling Complex Adaptive Systems As If They Were Voting Processes. This report summarizes the eight symposia.


Learning and Evaluating Human-Like NPC Behaviors in Dynamic Games

AAAI Conferences

We address the challenges of evaluating the fidelity of AI agents that are attempting to produce human-like behaviors in games. To create a believable and engaging game play experience, designers must ensure that their non-player characters (NPCs) behave in a human-like manner. Today, with the wide popularity of massively-multi-player online games, this goal may seem less important. However, if we can reliably produce human-like NPCs, this can open up an entirely new genre of game play. In this paper, we focus on emulating human behaviors in strategic game settings, and focus on a Social Ultimatum Game as the testbed for developing and evaluating a set of metrics for comparing various autonomous agents to human behavior collected from live experiments.