Publications

2019

1. [PAM] Spectrum Protection from Micro-Transmissions using Distributed Spectrum Patrolling Mallesham Dasari, Muhammad Bershgal Atigue, Arani Bhattacharya, and Samir R Das In Passive and Active Measurement 2019 Abs PDF

   RF spectrum is a limited natural resource under a significant demand and thus must be effectively monitored and protected. Recently, there has been a significant interest in use of small inexpensive spectrum sensors for large-scale RF spectrum monitoring. The spectrum sensors are attached to compute devices for signal processing computation and also network and storage support. However, these compute devices are very resource limited in terms of hardware, and thus the sensing parameters used in general, cannot be directly applied as is. To demonstrate this, we consider detecting an unauthorized transmitter that transmits intermittently for very small durations (micro-transmissions) as an example application. We quantify the impact of device hardware and crucial sensing parameters such as sampling rate, integration size and frequency resolution in detecting such transmissions. We find that we cannot detect more than 45% of micro-transmissions on these inexpensive spectrum sensors. To counter this, we show that almost all the micro-transmissions can be detected by deploying more sensors in a given location and fusing the data from multiple sensors.

2. [IFIP Networking] Advancing User Quality of Experience in 360 Degree Video Streaming Sohee Kim Park, Arani Bhattacharya, Zhibo Yang, Mallesham Dasari, Dimitris Samaras, and Samir R Das In 2019 IFIP Networking Conference 2019 Abs PDF

   Conventional streaming solutions for streaming 360-degree panoramic videos are inefficient in that they download the entire 360-degree panoramic scene, while the user views only a small sub-part of the scene called the viewport. This can waste over 80% of the network bandwidth. We develop a comprehensive approach called Mosaic that combines a powerful neural network-based viewport prediction with a rate control mechanism that assigns rates to different tiles in the 360-degree frame such that the video quality of experience is optimized subject to a given network capacity. We model the optimization as a multi-choice knapsack problem and solve it using a greedy approach. We also develop an end-to-end testbed using standards-compliant components and provide a comprehensive performance evaluation of Mosaic along with four other streaming techniques – two for conventional adaptive video streaming and two for 360-degree tile-based video streaming. Mosaic outperforms the best of the competition by as much as 50% in terms of median video quality.

2018

1. [IMC] Impact of Device Parameters on QoE of Internet-based Mobile Applications Mallesham Dasari, Santiago Vargas, Arani Bhattacharya, Samir R Das, Aruna Balasubramanian, and Michael Ferdman In ACM Internet Measurement Conference 2018 Abs PDF

   A large fraction of users in developing regions use relatively inexpensive low-end smartphones. However, the impact of device capabilities on the performance of mobile Internet applications has not been explored. In order to bridge this gap we study the QoE of three popular applications: Web browsing, video streaming, and telephony, for different device parameters. Our results demonstrate that the Web applications are much more sensitive to low-end hardware compared to video applications, especially video streaming. This is because the video applications exploit specialized coprocessors/accelerators and thread level parallelism on multi-core mobile devices. Even low-end devices are equipped with coprocessors and multiple cores. Whereas, Web browsing is largely influenced by clock frequency and uses no more than 2 cores. This makes Web browsing more vulnerable to performance on low-end smartphones. Based on the lessons learnt from studying video applications, we explore offloading Web computation to a co-processor. Specifically, we explore offloading of regular expression computation to a DSP coprocessor and show an improvement of 18% in page load time while saving the energy by a factor of 4.

2. [IWQoS] Scalable Ground-Truth Annotation for Video QoE Modeling in Enterprise WiFi Mallesham Dasari, Shruti Sanadhya, Christina Vlachou, Kyu-Han Kim, and Samir R Das In 2018 IEEE/ACM 26th International Symposium on Quality of Service 2018 Abs PDF

   Mobile video traffic is dominant in cellular and enterprise wireless networks. With the advent of myriads of applications from video telephony and streaming to virtual reality, network administrators face the challenge to provide high quality of experience (QoE) in the face of diverse wireless conditions and application contents. Yet, state-of-the-art networks lack analytics for QoE, as this requires support from the application or user feedback. While there are existing techniques to map quality of service (QoS) to QoE by training machine learning (ML) models without requiring user feedback, these techniques are limited to only few applications (e.g., Skype), due to insufficient QoE ground-truth annotation for ML. To address these limitations, we focus on video telephony applications and model key artefacts of spatial and temporal video QoE. Our key contribution is designing content- and device-independent metrics and training across diverse WiFi conditions. We show that our metrics achieve a median 90% accuracy by comparing with mean-opinion-score (MOS) from more than 200 users and 800 video samples. Our content-independent metrics significantly reduce the MOS prediction error of previous works and are validated over three popular video telephony applications - Skype, FaceTime and Google Hangouts.

2017

1. [SIGCOMM POSTER] Demystifying Hardware Bottlenecks in Mobile Web Quality of Experience Mallesham Dasari, Conor Kelton, Javad Nejati, Aruna Balasubramanian, and Samir R Das In Proceedings of the SIGCOMM Posters and Demos 2017

2016