Overlapping users of social networks such as Facebook and Twitter link these online social networks into a multiplex of social networks. As different components of the multiplex may have different properties, the multiplex may exhibit emergent phenomena that isn’t present in the simpler case of single layer social networks. For example, diffusion is likely to occur by different processes and with different speeds; therefore, one problem we consider is the diffusion of influence in a heterogeneous multiplex: where each layer has a different model of diffusion. Given this heterogenity of diffusion, new approaches to problems such as Influence Maximiation (IM) and Threshold Activation Problem (TAP) may be necessary.
Objectives:
- Determine emergent phenomena arising from the added multiplex complexity
- Study heterogeneous diffusion processes and related problems
- Study problems where the diffusion speed are different for networks
Selected Publications:
- . “Supporting a Storm: The Impact of Community on GamerGate’s Lifespan,” in IEEE Transactions on Network Science and Engineering, 2019
- . “Least Cost Influence Maximization Across Multiple Social Networks,” in IEEE Transactions on Networking (ToN), 2015
- . “Least Cost Influence in Multiplex Social Networks: Model Representation and Analysis,” in Proceedings of the IEEE Int Conference on Data Mining (ICDM), 2013
Smart Grid addresses the problem of existing powergrid\’s increasing complexity, growing demand and requirement for greater reliability, through two-way communication and automated residential load control among others. These features also makes the Smart Grid a target for a number of cyber attacks. The load profiles of consumers could be changed through the fabrication of price messages. This attack could lead to cascading failures. Our work is the first attempt to study the effect of such cyber attacks on smart grid, seeking the vulnerable critical nodes. With linearized DC power flow model and cascading failure in power grid models, we also provide solutions to mitigate or reduce the damage due to the cascading failures.
Objectives:
- Find vulnerable nodes where price modification attacks have potential to cause large blackouts
- Find measures to mitigate the cascading failures due to price modification attacks
Selected Publications:
- . “Price Modification Attack and Protection Scheme in Smart Grid,” in IEEE Transactions on Smart Grid, 2016
- . “Rate Alteration Attacks in Smart Grid,” in Proceedings of the IEEE Int Conference on Computer Communications (INFOCOM), 2015
- . “Cascading Critical Nodes Detection with Load Redistribution in Complex Systems,” in Proceedings of the 8th Annual International Conference on Combinatorial Optimization and Applications (COCOA), 2014
Supervisory Control And Data Acquisition (SCADA) system remotely monitors and controls remote stations from a central SCADA center through coded signals over communication (or control) network. The addition of control network to better manage and gather system data comes with its own set of vulnerabilities including false data injection and fabricated system data which leads to bad state estimation. Among security enhancements such as advanced encryption and authentication, deep packet inspection (DPI) is used to detect malicious packets. However, DPI introduces delay in the poacket transmission in highly time critical IEC 61850 messages. Our work focus on the placement of the DPIs in the control network in order to maximize the amount of scanned packets.
Objectives:
- To optimally place the DPIs in the control network without violating the time delay constraint
- Investigate other ways to detect malicious packets in SCADA network
Selected Publications:
- . “Auditing on Smart-Grid with Dynamic Traffic Flows: An Algorithmic Approach,” in IEEE Transactions on Smart Grid, 2019
- . “Optimal Inspection Points for Malicious Attack Detection in Smart Grids,” in Proceedings of the 20th Int Computing and Combinatorics Conference (COCOON), 2014
Although Device-to-device (D2D) communications over licensed wireless spectrum has been recently proposed as a promising technology to meet the capacity crunch of next generation cellular networks, the success, to a large extent, depends on the willingness of the participating devices to share their resources. Consideration of social aspect of human communication can go a long way in extracting efficient solutions to offload cellular traffic. However, due to the high mobility of cellular devices, establishing and ensuring the success of D2D transmission becomes a major challenge. Social aware community based approaches are shown to be useful in identifying a set of reliable relay devices that help a content to be transmitted from a source/cache to a destination.
Objectives:
- Devise novel framework to form multi-hop D2D connections in an effort to maximize time sensitive real-time content delivery
- Design a practical model to predict devise mobility coupled with physical radio network design aspects for transmitting delay-sensitive content
- Devise efficient multicast scheme to leverage similar content request in a particular location for offloading base station traffic
In cellular networks, rapid increase of data consumption has strained the network infrustructure. Proximity based device-to-device communication has been introduced as a way forward in next generation LTE networks. However, assigning limited resources efficiently to enable maximum reuse with spectral efficiency still remains an important challenge. As devices enter and leave a network frequently in an online manner, the solution framework must be able to work adaptively. The resource allocation algorithm should be fast and light because of the instantaneous nature of ever increasing content demand.
Objectives:
- Propose efficient resource reuse scheme considering inband interference management between cellular and D2D users.
- Design online and adaptive algorithm with performance guarantee for resource allocation in D2D underlaying cellular network
- Suggest new ways to incorporate social aware encounter based information in designing and identifying proper devices that facilitate maximum resource utilization
Selected Publications:
- . “Online set multicover algorithms for dynamic D2D communications,” in Journal of Combinatorial Optimization, 2017
- . “Online Algorithms for Optimal Resource Management in Dynamic D2D Communications,” in Proceedings of the IEEE 10th International Conference on Mobile Ad-hoc and Sensor Networks (MSN), 2014
The social computing will integrate and enhance many digital systems over the next decade and the smart grid is no exception. Smart grid efficiency depends on utility customers having knowledge about demand response programs and being actively engaged in energy management. And this is exactly where social network comes into the picture and can really have an impact. Social computing can also expand the adoption and adaptation of smart grid technologies through the peer to peer communication in local communities through social network. It also could change large scale behavior through crowdshifting basing on the theory “people decide how to behave based on what they see others doing, especially if those others seem similar to themselves”.
Objectives:
- Study and analyze the inter dependency between social network and smart grid
- Explore possible vulnerabilities and corresponding protection measures in the socially enabled smart grid
Publications:
- . “Catastrophic Cascading Failures in Power Networks,” in Theoretical Computer Science, 2015
he study of interdependent networks from the perspective of vulnerability seeks to identify the critical elements with respect to a variety of measures. An interdependent system is robust if external perturbations do not significantly impair the functionality of the system. In this area, we seek to design methods to identify the critical elements. One measure we study in general interdependent networks is the vulnerability of network clustering to node failure. We also study measures in practical scenarios, one scenario is in a Smart Grid system, how the interdependent communication and power networks impact one another’s functionality — a failure in one of these networks may cascade to the other. Another scenario is in mobile social networks underlay a D2D network, where misinformation in the social network may cascade and cause users stop using D2D, thus impact the throughput of the D2D network.
Objectives:
- Characterize robustness using a variety of measures of functionality
- Study interdependency effects relevant to vulnerability, such as cascading failure
- Identify critical elements in the functionality of interdependent systems
Selected Publications:
- . “Detecting Critical Nodes in Interdependent Power Networks for Vulnerability Assessment,” in IEEE Transactions on Smart Grid (ToSG), 2013