Work Experience

  • 2017

    Post-doc Reseracher

    Microsoft Research Lab (MSR), India

  • 2016

    Intern

    Systems Group, Microsoft Research Lab (MSR), India

  • 2013

    Visiting Researcher

    Distributed Information Systems Laboratory (LSIR)

    École polytechnique fédérale de Lausanne EPFL, Lausanne

  • 2012

    Research Assistant

    École polytechnique fédérale de Lausanne EPFL, Lausanne

  • 2012 2010

    Research Assistant

    Zero Energy Networks Laboratory, Department of Electronic Systems Engineering

    Indian Institute of Science IISc, India

Education

  • Ph.D2013 - 2016

    Ph.D.

    Delft University of Technology

  • B.E

    Bachelor of Engineering in Computer Science

    Visvesvaraya Technological University

News

Research Projects

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    iCore

    iCore initiative addresses two key issues in the context of the Internet of Things (IoT), namely how to abstract the technological heterogeneity that derives from the vast amounts of heterogeneous objects, while enhancing reliability and how to consider the views of different users.

    The iCore proposed solution is a cognitive framework comprising three levels of functionality,reusable for various and diverse applications. The levels under consideration are virtual objects(VOs), composite virtual objects (CVOs) and functional blocks for representing the user/stakeholder perspectives.

    VOs are cognitive virtual representations of real‐world objects (e.g. sensors, devices, everyday objects) that hide the underlying technological heterogeneity. CVOs, on the other hand are cognitive mash‐ups of semantically interoperable VOs, delivering services in accordance with the user/stakeholder requirements. The iCore solutions will be equipped with essential security protocols/functionality, which span all levels of the framework, and consider the ownership and privacy of data, as well as controlling the actual access to objects. To validate the proposed solutions iCore addresses the following usecases: ambient assisted living, smart office, smart transportation, and supply chain management.
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    Joule Jotter

    We aim to develop a publicly available dataset of energy consumption information for residential settings..

    Joule Jotter is a Joint project between DESE, Indian Institute of Science and Embedded Software, EEMCS, TUDelft. Joule Jotter project has received funding from ACM SIGCOMM Community project.

    In this project, we aim to develop a publicly available dataset of energy consumption information for residential settings. An in-house energy-monitoring device called “Joule Jotter” is used to monitor energy usage of individual appliances and also total energy usage of house and buildings. As a first step we would extensively gather the power readings from various houses and offices.

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Temporal Self-regulation of Energy Demand

Akshay Uttama Nambi S.N., Evangelos Pournaras and Venkatesha Prasad
Journal Papers In Transactions on Industrial Informatics, IEEE.

Abstract

The increase in deployment of smart meters has enabled collection of fine-grained energy consumption data at consumer premises. Analysis of this real-time energy consumption data bestows new opportunities for better demand-response (DR) programs. This work offers a new perspective to study energy demand and helps in designing novel mechanisms for decentralized demand-side management. Specifically, a new concept of finding the demand states using energy consumption of consumers over time and, feasible transitions therein, are introduced. It is shown that the orchestration of temporal transitions between the demand states can meet broad range of Smart Grid objectives. An online demand regulation model is developed that captures the temporal dynamics of energy demand to identify target consumers for different DR programs. This methodology is empirically evaluated and validated using data from more than 4000 households, which were part of a real-world Smart Grid project. This work is the first one to comprehensively analyze the temporal dynamics of demands.

iLTC: Achieving Individual Comfort in Shared Spaces

Chayan Sarkar, Akshay Uttama Nambi S.N., Venkatesha Prasad
Conference Papers In International Conference on Embedded Wireless Systems and Networks , EWSN 2016.

Abstract

Automatic control of HVAC and artificial lights has been one of the popular methods for achieving energy-efficient buildings. The current systems operate using fixed setpoint controls, which are usually based on a conservative approach. Moreover, the lighting systems require additional sensor deployment to cope up with continuous fluctuation of natural light intensity. In this work, we describe a smart system called indoor Lighting and Temperature Controller (iLTC), which eliminates the fixed set-points and requirement of additional light sensors. iLTC decides operating set-points more aggressively, which is energy optimal and tries to provide maximal user comfort to all the co-occupants in a shared space. The flexibility in choosing energy optimal set-points stems from the knowledge of comprehensive temperature and lighting comfort functions of individuals. To track the fluctuations in natural light intensity, we employ a smart estimation technique that requires light measurements only during the training phase. Using the proposed distributed system, we show the energy consumption of HVAC can be reduced up to 39%. Similarly, compared to traditional on/off based and multilevel lighting systems with iLTC, energy consumption can be reduced up to 33% and 60%, respectively. We also provide qualitative user experience evaluation.

LocED: Location-aware Energy Disaggregation Framework

Akshay Uttama Nambi S.N., Antonio Reyes Lua, Venkatesha Prasad
Conference Papers In 2nd ACM International Conference on Embedded Systems For Energy-Efficient Built Environments, BuildSys 2015.

Abstract

Providing detailed appliance level energy consumption in- formation may lead consumers to understand their usage behavior and encourage them to optimize the energy usage. Non-intrusive load monitoring (NILM) or energy disaggre- gation aims to estimate appliance level energy consumption from the aggregate consumption data of households. NILM algorithms, proposed hitherto, are either centralized or do require high performance systems to derive appliance level data, owing to the computational complexity associated. This approach raises several issues related to scalability and privacy of consumer’s data. In this paper, we present the Location-aware Energy Disaggregation Framework (LocED) that utilizes occupancy of users to derive accurate appli- ance level usage information. LocED framework limits the appliances considered for disaggregation based on the cur- rent location of occupants. Thus, LocED can provide real- time feedback on appliance level energy consumption and run on an embedded system locally at the household. We propose several accuracy metrics to study the performance of LocED. To test the robustness of LocED, we empiri- cally evaluated it across multiple publicly available datasets. LocED has significantly high energy disaggregation accuracy while exponentially reducing the computational complexity. We also release our comprehensive dataset DRED (Dutch Residential Energy Dataset) for public use, which measures electricity, occupancy and ambient parameters of the household.

DIAT: A Scalable Distributed Architecture for IoT

C. Sarkar, Akshay Uttama Nambi S.N., Prasad R, Rahim A, Neisse R, Baldini G
Journal Papers In Internet of Things Journal, IEEE , vol.PP, no.99, pp.1,1, 2015.

Abstract

The advent of Internet of Things (IoT) has boosted the growth in number of devices around us and kindled the possibility of umpteen number of applications. One of the major challenges in the realization of IoT applications is interoperability among various IoT devices and deployments. Thus, the need for a new architecture – comprising of smart control and actuation – has been identified by many researchers. In this article, we propose a Distributed Internet-like Architecture for Things (DIAT), which will overcome most of the obstacles in the process of large scale expansion of IoT. It specifically addresses heterogeneity of IoT devices, and enables seamless addition of new devices across applications. In addition, we propose an usage control policy model to support security and privacy in a distributed environment. We propose a layered architecture that provides various levels of abstraction to tackle the issues such as, scalability, heterogeneity, security and interoperability. The proposed architecture is coupled with cognitive capabilities that helps in intelligent decision making and enables automated service creation. Using a comprehensive use-case, comprising elements from multiple-application domains, we illustrate the usability of the proposed architecture.

Zero Energy Network stack for Energy Harvested WSNs

Akshay Uttama Nambi S.N., T V Prabhakar, Venkatesha Prasad, H S Jamadagni
Journal Papers

Abstract

We present our ``Zero Energy Network'' (ZEN) protocol stack for energy harvesting wireless sensor networks applications. The novelty in our work is 4 fold: (1) Energy harvesting aware fully featured MAC layer. Carrier sensing, Backoff algorithms, ARQ, RTS/CTS mechanisms, Adaptive Duty Cycling are either auto configurable or available as tunable parameters to match the available energy (b) Energy harvesting aware Routing Protocol. The multi-hop network establishes routes to the base station using a modified version of AODVjr routing protocol assisted by energy predictions. (c) Application of a time series called ``Holt-Winters'' for predicting the incoming energy. (d) A distributed smart application running over the ZEN stack which utilizes a multi parameter optimized perturbation technique to optimally use the available energy. The application is capable of programming the ZEN stack in an energy efficient manner. The energy harvested distributed smart application runs on a realistic solar energy trace with a three year seasonality database. We implement a smart application, capable of modifying itself to suit its own as well as the network's energy level. Our analytical results show a close match with the measurements conducted over EHWSN testbed.

Performance Analysis of Data Processing Architectures for the Smart Grid

Akshay Uttama Nambi S.N., Matteo Vasirani, Venkatesha Prasad, Karl Aberer
Conference Papers In 5th IEEE PES Innovative Smart Grid Technologies (ISGT) European 2014 Conference.

Abstract

Information and communication technology infras- tructures play an important role to realize the full potential of Smart Grid (SG) applications. Several architectures proposed in the literature usually focus on communication requirement or data storage. However, it is still not clear which architecture best satisfies energy, storage, processing and communication requirements. The lack of understanding of key parameters, such as energy required, communication bandwidth, storage space, processing power, etc., has hindered the large scale SG deploy- ments. In this paper, we investigate different data processing architectures for hierarchical power distribution networks. We introduce several key cost indicators to analyze hierarchical data processing architectures for the SG. In our evaluation, we consider realistic deployments in both dense and sparse environments and provide a detailed performance analysis of the proposed architectures. The results reported here are significant for SG designers, who can use them to discern the architecture that best fits the system requirements.

On systems generating context triggers through energy harvesting

Vijay S Rao, Akshay Uttama Nambi S.N., Venkatesha prasad and I. Niemegeers
Journal Papers In Communications Magazine, IEEE Vol. 52 Issue 6:70-77.

Abstract

Context awareness is one of the building blocks of smart applications that constitutes smart spaces. With the emergence of cyber physical systems, it is now possible to create spaces that are truly adaptable and smart. In these spaces, contextual parameters are captured by many wireless sensor nodes. This collected data is processed to understand the context in real time. Since a large number of sensors are deployed, processing all the data is a big task. Moreover, since the sensors are powered by batteries, they have a limited lifetime. Sensing only when there is a context event can save energy as well as reduce data processing. To make sensor nodes operate perpetually, ambient energy harvesters can be used. Typically, the energy harvesting source of a sensor is related to the physical parameters the sensor is measuring. We propose exploiting this property to develop a context-event triggering mechanism in this article. We also adapt the context-aware application framework for incorporating context-event triggers by harvesters. A Smart-M3-based architecture is also proposed. Through a real-world use case, we illustrate significant energy savings and reduced data processing in our proposed approach.

A Cost-Benefit Analysis of Data Processing Architectures for the Smart Grid.

Akshay Uttama Nambi S.N., Matteo Vasirani, Venkatesha Prasad, Karl Aberer
Conference Papers Wireless and Mobile Technologies for Smart Cities (WiMobCity) with ACM International Symposium on Mobile Ad Hoc Networking and Computing (MobiHoc'14).

Abstract

Information and communication technology (ICT) infras- tructure plays an important role to realize the full poten- tial of Smart Grid applications. Smart grids utilize ICT entities to enhance efficiency, reliability and sustainability of power generation and distribution network. Majority of the architectures proposed hitherto focus only on a specific architectural aspect, like communication, storage, process- ing requirement, etc. Recent studies have shown that lack of knowledge on which architecture best satisfies certain infor- mation management requirements has hindered large scale smart grid deployments. In this paper, we investigate the cost-benefit analysis of four data processing architectures for various applications in smart grid. We introduce several key cost indicators to analyze hierarchical data processing architectures for the smart grid. In our evaluation, we con- sider realistic deployments for both dense and sparse envi- ronments. Results reported here are significant for smart grid designers, who can use them to discern the architecture that best fits the system requirements.

A Unified Semantic Knowledge Base for IoT

Akshay Uttama Nambi S.N., Chayan Sarkar, R Venkatesha Prasad, Abdur Rahim
Conference Papers in IEEE World Forum on Internet of Things WF-IoT 2014.

Abstract

In the Internet of Things (IoT), interoperability among heterogeneous entities is an important issue. Semantic modeling is a key catalyst to support interoperability. In this work, we present a unified semantic knowledge base for IoT that uses ontologies as the building blocks. Most of the current ontologies for IoT mainly focus on resources, services and location information. We build upon the current state-of-the-art ontologies to provide contextual information and set of policies to execute services. Our knowledge base consists of several ontologies viz, resource, location, context & domain, policy and service ontologies. This helps in building a unified knowledge representation for IoT entities. In our knowledge base, we specifically model dynamic environments in which IoT entities operate. Our knowledge base also facilitates service- composition, discovery and modeling for IoT in dynamic environments.

A Scalable Distributed Architecture Towards Unifying IoT Applications

Chayan Sarkar, Akshay Uttama Nambi S.N., R Venkatesha Prasad, Abdur Rahim
Conference Papers in IEEE World Forum on Internet of Things WF-IoT 2014.

Abstract

The advent of Internet of Things (IoT) has kindled the possibility of umpteen number of applications. One of the major challenges in the realization of IoT applications is interoperability among various IoT entities. Thus, the need for a new architecture - comprising of smart control and actuation - has been identified by many researchers. In this article, we propose a distributed, interoperable architecture for IoT, which will overcome most of the obstacles in the process of large scale expansion of IoT. It specifically addresses heterogeneity of IoT devices, and allows for new devices to be added seamlessly across applications. We propose a layered architecture that provides various levels of abstraction to tackle scalability, heterogeneity and interoperability. Using a comprehensive study of a use-case, comprised of elements from multiple-application domains, we illustrate the usability of the proposed architecture.

Sustainable Energy Consumption Monitoring in Residential Settings

Akshay Uttama Nambi S.N., Thanasis Papaioannou, Dipanjan Chakraborty, Karl Aberer
Conference Papers In proceedings of IEEE INFOCOM, Turin, Italy, April 14-19, 2013.

Abstract

The continuous growth of energy needs and the fact that unpredictable energy demand is mostly served by unsustainable (i.e. fossil-fuel) power generators have given rise to the development of Demand Response (DR) mechanisms for flattening energy demand. Building effective DR mechanisms and user awareness on power consumption can significantly benefit from fine-grained monitoring of user consumption at the appliance level. However, installing and maintaining such a monitoring infrastructure in residential settings can be quite expensive. In this paper, we study the problem of fine-grained appliance power-consumption monitoring based on one house-level meter and few plug-level meters. We explore the trade-off between monitoring accuracy and cost, and exhaustively find the minimum subset of plug-level meters that maximize accuracy. As exhaustive search is time- and resource-consuming, we define a heuristic approach that finds the optimal set of plug-level meters without utilizing any other sets of plug-level meters. Based on experiments with real data, we found that few plug-level meters - when appropriately placed - can very accurately disaggregate the total real power consumption of a residential setting and verified the effectiveness of our heuristic approach.

An implementation study of relay selection schemes for energy harvesting WSNs

Prabhakar, T.V., Akshay Uttama Nambi S N, S.N., Iyer, M., Jamadagni, H.S., Venkatesha Prasad, R., Niemegeers, I.G.M.M.
Conference Papers In Consumer Communications and Networking Conference (CCNC), 2013 IEEE, pp. 733-736.

Abstract

We propose energy harvesting technologies and cooperative relaying techniques to power the devices and improve reliability. We propose schemes to (a) maximize the packet reception ratio (PRR) by cooperation and (b) minimize the average packet delay (APD) by cooperation amongst nodes. Our key result and insight from the testbed implementation is about total data transmitted by each relay. A greedy policy that relays more data under a good harvesting condition turns out to be a sub optimal policy. This is because, energy replenishment is a slow process. The optimal scheme offers a low APD and also improves PRR.

Smart Network Interface Selection for E-DTNs

Prabhakar T.V, Akshay Uttama Nambi S.N, R Venkatesha Prasad, Jamadagni H.S, I.G.M.M. Niemegeers
Conference Papers In proceedings of ninth annual IEEE Consumer Communications and Networking Conference, CCNC 2012.

Abstract

We implement two energy models that accurately and comprehensively estimates the system energy cost and communication energy cost for using Bluetooth and Wi-Fi interfaces. The energy models running on a system is used to smartly pick the most energy optimal network interface so that data transfer between two end points is maximized.

E-DTN : A Multi Interface Energy DTN Gateway

Prabhakar T.V, Akshay Uttama Nambi S.N, Jamadagni H.S, Sudhangathan B.S.
Workshop Papers In proceedings of fifth annual workshop on “WIreless Systems: Advanced Research and Development”, WISARD 2011 part of COMSNETS, January 2011.

Abstract

We implement two energy models that accurately and comprehensively estimates the system energy cost and communication energy cost for using Bluetooth and Wi-Fi interfaces. The energy models running on a system is used to smartly pick the most energy optimal network interface so that data transfer between two end points is maximized.

Bond Graph Modeling for Energy Harvested WSN's

Prabhakar T.V, Akshay Uttama Nambi S. N, R Venkatesha Prasad, I.G.M.M Niemegeers,
Journal Paper In proceedings of IEEE Computer Magazine, 2012.

Abstract

Researchers can use bond graph modeling, a tool that takes into account the energy conservation principle, to accurately assess the dynamic behavior of wireless sensor networks on a continuous basis.

Near Field Communication - Applications and Performance Studies (Best Paper Award)

Akshay Uttama Nambi S N, Prabhakar T V, Jamadagni H.S., et al.
Journal Paper In proceedings of Sixth International Conference on Information Processing (ICIP- 2012), Springer Verlag in the series of Communications in Computer and Information Science (CCIS) August 2012.

Abstract

Near Field Communication (NFC), is an integration of Radio Frequency Identification (RFID) technology with mobile devices. NFC offers a quick and convenient method of interaction between humans and NFC enabled devices. Current research concerning NFC appears to mainly focus on development of NFC enabled applications and services. In this paper, we study the performance of NFC devices by considering metrics such as achieved data rates and received power for several distances. Knowledge of these metrics may be useful for application developers to build applications efficiently. We have developed various applications on NFC enabled devices for public transport systems. We also describe the design of 13.56 MHz antenna which was used for measurements of the received power.

A Distributed Smart Application for Solar Powered WSNs

Prabhakar T.V, Akshay Uttama Nambi S. N, R Venkatesha Prasad, Shilpa S, Prakruthi K, I.G.M.M Niemegeers,
Journal Paper In proceedings of 11th International IFIP TC 6 Networking Conference, Lecture Notes in Computer Science, Vol. 7290, May 2012.

Abstract

Energy harvesting (EH) is a major step in solving the critical issue of availability of energy for sensor nodes. However, it throws many challenges. The applications built on the sensor networks powered by EH need to adapt their operations yet serve the purpose. We propose a distributed smart application for a multihop sensor network and in general in the future Internet of Things (IoT) where a network node executes an optimal number of policies to minimize the difference between available energy and consumed energy (called residual energy) for the execution of an application policy. We formulate this as a multi-criteria optimization problem and solve it using linear programming Parametric Analysis. We demonstrate our approach on a testbed with solar panels. We also use a realistic solar energy trace with a three year database including seasonality. The smart application is capable of adapting itself to its current energy level as well as that of the network. Our analytical results show a close match with the measurements conducted over testbed.

A Novel DTN based Energy Neutral Transfer Scheme for Energy Harvested WSN Gateways

Prabhakar T.V, Akshay Uttama Nambi S.N, Krishna Swaroop, Jamadagni H.S.,
Journal Paper In the journal of ACM SIGMETRICS Performance Evaluation Review (PER) 2010, December 2010.

Abstract

To overcome the problem of unavailability of grid power in rural India, we explore the possibility of powering WSN Gateways using a bicycle dynamo. The "data mule" bicycle generates its own power to ensure a self sustainable data transfer scheme to benefit small and marginal farmers. In our agricultural scenario, farmers have to generate electricity to get access to the technology. Our power measurements show that it is indeed possible to drive GPRS technologies with this power. We propose Transfer Energy Budget - a two way metric for gateway nodes to announce the available energy for relaying data. To achieve our goal, we exploit the DTN stack in the energy sense and introduce necessary modifications to its configuration. The results indicate that a 50 packet buffer has the least transfer energy budget with a data latency of about 31 seconds.

A Novel DTN based Energy Neutral Transfer Scheme for Energy Harvested WSN Gateways

Prabhakar T.V, Akshay Uttama Nambi S.N, Jamadagni H.S, Krishna Swaroop, R Venkatesha Prasad, I.G.M.M. Niemegeers
Workshop Papers In proceedings of ACM GreenMetrics 2010, in conjunction with ACM SIGMETRICS, June 2010.

Abstract

To overcome the problem of unavailability of grid power in rural India, we explore the possibility of powering WSN Gateways using a bicycle dynamo. The "data mule" bicycle generates its own power to ensure a self sustainable data transfer scheme to benefit small and marginal farmers. In our agricultural scenario, farmers have to generate electricity to get access to the technology. Our power measurements show that it is indeed possible to drive GPRS technologies with this power. We propose Transfer Energy Budget - a two way metric for gateway nodes to announce the available energy for relaying data. To achieve our goal, we exploit the DTN stack in the energy sense and introduce necessary modifications to its configuration. The results indicate that a 50 packet buffer has the least transfer energy budget with a data latency of about 31 seconds.

A Domain Independent Approach to Semantic Enabling of Structured Data

Preethy Iyer, Srividya Gopalan, Akshay Uttama Nambi S.N, Niranjan Manjunath, Ginu George, Basavaraju M.
Conference Papers In proceedings of International Conference on Sensors, Security, Software and Intelligent Systems, ISSSIS 2009.

Abstract

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Teaching Assistant

  • Present

    Ad-hoc Networks

  • 2014-15

    Ad-hoc Networks

    Smart Phone Sensing

  • 2013-14

    Internet of Things seminar

    Ad-hoc Networks

    Smart Phone Sensing

Professional Activities

  • 2016

    IPSN, ICC, E2Nets, SmartGridComm

  • 2015

    SenSys, ICC, Mobiqutous, EWSN, SmartGridComm, ICC, WF-IoT

  • 2014

    SenSys, SECON, ICC, Globecom, E2Nets, WiMobCity, goSMART, WF-IoT

  • 2013

    ICC, Globecom, E2Nets

  • 2011-12

    ICC, NCC

Other Activities

At My Office

My office is located at the HB 09.070, 9th Floor, Embedded Software Group in EEMCS, TUDelft, Mekelweg 4, 2628 CD, Delft.