Department of Computer Science and Engineering

Indian Institute of Technology Hyderabad (IITH) is a premier institute of science and technology established in 2008. IITH has been consistently ranked in the&nbsp;<a href="https://iith.ac.in/reports/" rel="noopener noreferrer">top 10 institutes</a>&nbsp;in India for Engineering&nbsp;<a href="https://www.nirfindia.org/2021/EngineeringRanking.html" rel="noopener noreferrer" target="_blank">according to NIRF</a>&nbsp;making it one of the most coveted schools for science and technology in the country.

IITH offers&nbsp;<a href="https://iith.ac.in/academics/under-graduate/">undergraduate programs</a>&nbsp;in all the classical engineering disciplines, applied sciences, design, as well as several modern interdisciplinary areas. Students are given a flexibility to explore a broad set of areas, and potentially pursue a minor or double major in a discipline that is not their own. Students who wish to seek a deeper understanding of their own discipline are strongly encouraged to get involved in cutting-edge research with the help of a faculty to mentor them, and earn an Honors in their own field.

The very foundation of IIT Hyderabad is based on&nbsp;<a href="https://iith.ac.in/research/">research and innovation</a>. The vibrant research culture is evident from the number of patents and publications that IITH produces consistently every year. IITH offers&nbsp;<a href="https://iith.ac.in/academics/programmes-offered/">graduate programs</a>&nbsp;at both a masters, and a doctoral level, in several diverse areas. There are separate programs for technology, design, science, and liberal arts. The&nbsp;<a href="https://iith.ac.in/academics/post-graduate/">MTech program</a>&nbsp;is offered in various modes and durations to cater to the ever-growing need of postgraduate level professionals in the country.

IITH encourages and supports&nbsp;<a href="https://iic-iith.netlify.app/index.html" rel="noopener noreferrer" target="_blank">innovation and entrepreneurship</a>&nbsp;at every stage. The minor program in entrepreneurship is open to all students of IITH, and many of the courses are offered by industrialists who are entrepreneurs themselves. There are various&nbsp;<a href="https://iith.ac.in/research/centres-incubators/">innovation centers and incubators</a>&nbsp;that promote entrepreneurship and help mentor young innovators. IITH has been very successful in building tie-ups with leading academic institutions around the globe.

IITH enjoys a very special relationship with Japanese universities and industries that goes beyond academic and research collaborations. In fact, some of the iconic buildings in IITH campus will carry the signature of Japanese architecture.

IITH creates a unique holistic ecosystem for education that offers interactive learning, a very flexible academic structure, cutting-edge research, strong industry collaboration, and entrepreneurship. This is an environment which enables students and faculty to translate their dreams into realities.

IIT Hyderabad

The mobile network operators are moving towards Virtual Network Functions (VNFs), in place of traditional dedicated hardwares for the 5G deployment. The VNFs require low maintenance and give high flexibility compared to dedicated hardwares which are prone to failures. Typically, VNFs are run on top of Virtual Machines (VMs) which run on physical nodes in data centers. For each class of service, based on its policy, the traffic has to pass through a set of VNFs in sequence termed as Service Function Chains (SFCs). Selection of available VNFs to steer the SFC requests with guaranteed end-to-end latency is still an open problem. In this work, we design an algorithm named DAVIS (Delay-Aware VNF selectIon algorithm for SFC) to increase the SFC acceptance rate by efficiently selecting VNFs. Simulation results show that DAVIS improves the throughput of accepted requests by 42% while guaranteeing SLA requirements. © 2019 IEEE.

World University root node

2019 11th International Conference on Communication Systems and Networks, COMSNETS 2019

DAVIS: A Delay-Aware VNF Selection Algorithm for Service Function Chaining

In this study, we investigate the flexible many-to-one mapping of central units (CUs) to compute servers in 5G Radio Access Network (5G-RAN) using two-sided matching theory considering spatio-temporal tidal traffic patterns. Initially, we use a well known bin-packing heuristic known as First Fit Decreasing (FFD) to obtain suboptimal CU to compute server mapping. To address the traffic heterogeneity, we formulate a novel strategy of dynamic reassignment (known as Machine Admission Game or MAG) among a set of CUs and compute server in each mapping interval, using analytical approaches of coalitional game theory and college admission game. To solve this, we devise a modified version of the classical Deferred Acceptance Algorithm (DAA) satisfying the resource constraints of compute servers. We assess the benefit of the proposed matching theory framework with baseline FFD in terms of compute resource multiplexing gain (i.e., number of active servers in the CU pool) and the number of relocations incurred in the dynamic reassignment of candidate CUs. We observe that the proposed MAG framework though consumes nearly 6.8% and 4.1% of more servers than baseline FFD, it reduces the number of relocations by 33.9% on weekdays and 25.7% on weekends as compared to FFD. © 2019 IEEE.

International Symposium on Advanced Networks and Telecommunication Systems, ANTS

A Matching-theoretic Framework for Consolidation of Flexible Cloud-native Central Units in 5G-RAN

With the exponential growth in mobile data traffic, mobile operators are facing the unfortunate limit on the availability of licensed spectrum which has however, led to the popularity of long term evolution (LTE) in unlicensed spectrum (LTE-U). Undeniably, it is expected from LTE-U that it fairly shares the spectrum with Wi-Fi. Along with fair sharing, efficient utilization of the unlicensed spectrum is also equally important, which in some sense requires coordination between the two radio access technologies (RATs) viz., LTE-U and Wi-Fi. In particular, the hidden terminal scenario between LTE-U and Wi-Fi, resulting mainly due to lack of coordination, threatens the spectrum utilization of unlicensed spectrum. Focusing on this hidden terminal problem between LTE-U and Wi-Fi, we highlight the deficiency of existing technologies from the Wi-Fi perspective, both at the user level and at the network level. We then propose a novel coexistence technique (similar to RTS-CTS mechanism in Wi-Fi) that solves the hidden terminal problem between LTE-U and Wi-Fi, and subsequently addresses the spectrum underutilization problem caused by hidden terminal collisions. The proposed mechanism achieves this by using a modified CTS frame of Wi-Fi. We have validated our proposed mechanism using a mathematical framework demonstrating its credibility. © 2015 IEEE.

Fulltext

IEEE Transactions on Cognitive Communications and Networking

A Complete Solution to LTE-U and Wi-Fi Hidden Terminal Problem

We provide a characterisation for the size of proofs in tree-like Q-Resolution and tree-like QU-Resolution by a Prover–Delayer game, which is inspired by a similar characterisation for the proof size in classical tree-like Resolution. This gives one of the first successful transfers of one of the lower bound techniques for classical proof systems to QBF proof systems. We apply our technique to show the hardness of three classes of formulas for tree-like Q-Resolution. In particular, we give a proof of the hardness of the parity formulas from Beyersdorff et al. (2015) [10] for tree-like Q-Resolution and of the formulas of Kleine Büning et al. (1995) [29] for tree-like QU-Resolution. © 2017 The Authors

Journal of Computer and System Sciences

A game characterisation of tree-like Q-Resolution size

The problem of constructing hazard-free Boolean circuits dates back to the 1940s and is an important problem in circuit design. Our main lower-bound result unconditionally shows the existence of functions whose circuit complexity is polynomially bounded while every hazard-free implementation is provably of exponential size. Previous lower bounds on the hazard-free complexity were only valid for depth 2 circuits. The same proof method yields that every subcubic implementation of Boolean matrix multiplication must have hazards. These results follow from a crucial structural insight: Hazard-free complexity is a natural generalization of monotone complexity to all (not necessarily monotone) Boolean functions. Thus, we can apply known monotone complexity lower bounds to find lower bounds on the hazard-free complexity. We also lift these methods from the monotone setting to prove exponential hazard-free complexity lower bounds for non-monotone functions. As our main upper-bound result, we show how to efficiently convert a Boolean circuit into a bounded-bit hazard-free circuit with only a polynomially large blow-up in the number of gates. Previously, the best known method yielded exponentially large circuits in the worst case, so our algorithm gives an exponential improvement. As a side result, we establish the NP-completeness of several hazard detection problems. © 2019 Copyright held by the owner/author(s).

Journal of the ACM

On the complexity of hazard-free circuits

Multicast is a one-To-many communication model that is important for video streaming like IPTV. However, multicast does not guarantee the reliability of data transfer, and packet loss beyond the performance of error correction mechanism introduce significant degradation of the quality of Multicast streaming. Monitoring quality of multicast streaming is difficult because a) generally intermediate multicast routers and switches do not maintain the fine-grained state about multicast flow and b) sampling QoS statistics from destination clients introduces significant operational overhead. Therefore, it is difficult to properly locate where packet losses happen and how severe they are. This paper proposes selective packet tagging based monitoring (SPTM) mechanism to detect and locate packet losses in real-Time using a packet tagging technique in Software-Defined Network(SDN). The proposed system also re-calculates the Multicast Delivery Tree(MDT) upon the detection of packet losses in the tree links. The evaluation results show the feasibility of the proposed approach to detect, locate as well as recover the MDTs from the packet loss. © 2019 Copyright held by the owner/author(s).

Proceedings of the Asian Internet Engineering Conference, AINTEC 2019

Tagging based Packet Loss Detection and Recovery of IP Multicast in SDN

Electronic Medical Records (EMRs) contain private and sensitive information of the patients and require distribution across multiple stakeholders for sustained and consistent medical care. EMRs are owned and maintained by hospital systems. So, patients often face difficulties in getting their data shared among different stakeholders. Blockchain provides distributed, transparent, and immutable log of records that benefit the design of healthcare systems. There have been several studies done to use Blockchain technology as a mediation tool for sharing sensitive EMRs between multiple stakeholders in the e-health care system. However, these studies lack the requirement of patients to have full control over their EMR data. This work develops PACEX, PAtient-Centric EMR eXchange, that enables patients to share and have complete control over their data using Blockchain. In PACEX, we develop an easy-to-use patient application that interacts with different hospital systems and handles EMR exchanges with integrity. We developed a proof of concept implementation of PACEX using Ethereum Blockchain and Smart Contracts to achieve access control and maintain a history of record exchanges among different stakeholders. The evaluation results provide the quantitative analysis that gives time estimates for various transactions involved in PACEX and the qualitative analysis that describes the security properties of the system. PACEX achieves essential security requirements such as Authentication, Integrity, Access Control, and Traceability over the EMR data exchange. © 2019 IEEE.

2019 IEEE 10th Annual Information Technology, Electronics and Mobile Communication Conference, IEMCON 2019

PACEX: PAtient-Centric EMR eXchange in Healthcare Systems using Blockchain

Software-Defined Networking (SDN) allows applications to control and manage the network from the northbound interface. These network applications can be installed by a third party; that cannot be trusted blindly. A Misconfigured or compromised application is a severe threat to the SDN controller. Providing proper access control mechanism to SDN applications can prevent malicious activities. However, the existing access control mechanisms define the static access permissions, and cannot prevent the malicious activities of the application at runtime. Therefore, we propose "BEAM", a BEhavior-based Access control Mechanism which dynamically grants the permissions based on the analysis of network behavior. BEAM periodically upgrades/downgrades the assigned access permissions, verifies and builds trust for an application. © 2019 IEEE.

Proceedings - International Conference on Computer Communications and Networks, ICCCN

BEAM: BEhavior-based access control mechanism for SDN applications

We propose a new attribution method for neural networks developed using first principles of causality (to the best of our knowledge, the first such). The neural network architecture is viewed as a Structural Causal Model, and a methodology to compute the causal effect of each feature on the output is presented. With reasonable assumptions on the causal structure of the input data, we propose algorithms to efficiently compute the causal effects, as well as scale the approach to data with large dimensionality. We also show how this method can be used for recurrent neural networks. We report experimental results on both simulated and real datasets showcasing the promise and usefulness of the proposed algorithm. © 2019 by the Author(S).

36th International Conference on Machine Learning, ICML 2019

Neural network attributions: A causal perspective

Lots of planned events (e.g. concerts, sports matches, festivals, etc.) keep happening across the world every day. In various applications like event recommendation, event reporting, etc. it might be useful to find user discussions related to such events from social media. Identification of event related hashtags can be useful for this purpose. In this paper, we focus on identifying the top hashtags related to a given event. We define a set of features for (event, hashtag) pairs, and discuss ways to obtain these feature scores. A linear aggregation of these scores is used to finally output a ranked list of top hashtags for the event. The aggregation weights of the features are obtained using a learning to rank algorithm. We establish the superiority of our method by performing detailed experiments on a large dataset containing multiple categories of events and related tweets. © Springer Nature Switzerland AG 2019.