Dr. Bhushan G. Jagyasi has been working as a Scientist at TCS-Innovation Labs, Mumbai, since July 2008. He has been involved in a rich array of research work in the fields of Distributed Detection, Signal Processing, Wireless Sensor Networks, and Mobile Phone based Sensor Networks. An Electronics and telecommunications Engineering graduate from Amravati University, Amravati, Dr. Jagyasi was awarded the Master’s in Engineering in Electronics by the Mumbai University, Mumbai in June 2000. Between 2002 and 2004, he held a faculty position at the Department of Electronics and Telecommunications engineering at the Thadomal Shahani Engineering College, Mumbai. Dr. Jagyasi further pursued his doctoral studies at the Department of Electrical Engineering, Indian Institute of Technology Bombay (IIT-B) and was awarded the Ph.D degree in 2009. During his Ph.D., he was also awarded the Philips India Fellowship in 2007.
Abstract:
Multihop Cellular Networks, Multihop Sensor Networks and Multihop Cellular Sensor Networks are fast-emerging, utilitarian multihop mobile networking paradigms that promise increased transmission rates and network capacity. Multihop Mobile Wireless Networks discusses issues pertaining to each of these networks and proposes novel and innovative algorithms on Scheduling, Routing and Data aggregation that are viable solutions for multihop mobile networks. Moreover, the book provides the preliminaries and an excellent review on existing approaches in wireless communications. Multihop Mobile Wireless Networks is suitable for academic and industrial research, and can be used for advanced courses in Senior Undergraduate and Graduate programs.
The key findings of the book are:
• Multihop Cellular Networks (MCN): These networks, as compared to the existing single-hop cellular networks, provide higher throughput and capacity at lower transmission power requirements by effective spectral re-use. A novel route discovery and resilience protocol, as well as a probability of error based link Scheduling algorithm have been proposed in this book.
• Multihop Sensor Networks (MSN): Wireless Sensor Networks are inherently multihop in nature, due to the limited transmission range of resource-constrained sensor nodes. This book presents a novel multibit distributed data aggregation scheme, which minimizes in-network communication, for an event detection application.
• Multihop Cellular Sensor Networks (MCSN): Cell phones empowered with sensing capabilities have resulted in the emergence of Cellular Sensor Networks which can impact urban sensing applications in a profound sense. This book advocates multihopping in Cellular Sensor Networks and demonstrates its utility in a moving event localization application. Novel data aggregation and routing protocols which take into consideration the underlying mobility model and time-varying connectivity in MCSN have been proposed.
Abstract: In cell phone sensor networks (CpSN), sensor-embedded cell phones communicate sensor data using Near Field Communication outlets such as Wi-Fi or Bluetooth. This paper considers a query dissemination application of CpSN, where sensor data belonging to a certain time window [ts,min, ts,max] is needed from a region of interest. Existing approaches, such as ADAPT, use adaptive broadcast ranges at the Wireless Access Point (WAP) for query dissemination. This paper proposes the adaptation of waiting time at nodes for energy-efficient query dissemination. The design and analysis of the proposed Spatio-Temporally Adaptive Distributed Velocity Dependent (STA-DVD) waiting time is presented. The STA-DVD protocol is analytically compared with a Spatially Adaptive Distributed Velocity Dependent (SA-DVD) waiting time based protocol. Simulation results show that STA-DVD has a superior querying performance in terms of number of samples procured than SA-DVD, at a slightly higher energy cost. For the case of a Randomized Waiting (RW) time adopted by nodes in ADAPT, the ADAPT-RW protocol has the best querying performance, with significantly high energy costs. STA-DVD has a comparable querying performance with ADAPT-RW, for high residual times and a better performance for low residual times, with significantly low energy dissipation.
Abstract: Cell phones are embedded with sensors form a Cellular Sensor Network which can be used to localize a moving event. The inherent mobility of the application and of the cell phone users warrants distributed structure-free data aggregation and on-the-fly routing. We propose a Distributed Velocity-Dependent (DVD) protocol to localize a moving event using a Multihop Cellular Sensor Network (MCSN). DVD is based on a novel form of connectivity determined by the waiting time of nodes for a Random Waypoint (RWP) distribution of cell phone users. This paper analyzes the time-stationary and spatial distribution of the proposed waiting time to explain the superior event localization and delay performances of DVD over the existing Randomized Waiting (RW) protocol. A sensitivity analysis is also performed to compare the performance of DVD with RW and the existing Centralized approach.
Abstract: The problem of decision fusion for event detection in Wireless Sensor Networks is the prime focus of this paper. Our proposed algorithm focuses on single hop (star) and multihop (tree) topologies, which are commonly deployed wireless sensor network topologies. In order to minimize the overall energy consumption in the network, a transmission constraint of one-bit is imposed on each sensor node. This poses a challenging problem of designing a one-bit decision fusion rule at every fusion center, which improves the overall detection accuracy at the sink node. The absence of apriori knowledge of each sensor’s local performance indices, makes the existing optimum fusion rule infeasible. Moreover, in the absence of a training sequence of true event occurrences, existing Adaptive distributed detection techniques also become inapplicable. In this setup, the key contribution of this paper is a Least Mean Squares based Blind Adaptive Weighted Aggregation Scheme (Blind-AdWAS) for Wireless Sensor Networks with tree topology. We extend our earlier work (Jagyasi et al. in Proceedings of 11th international symposium on wireless personal multimedia communication, 2008) to include an analysis of the effect of Rayleigh flat fading channel on Blind-AdWAS in comparison with existing channel-aware optimum and sub- optimum aggregation schemes. Even in the absence of any channel knowledge or knowledge of performance indices, Blind-AdWAS demonstrates robustness in event detection performance.
Abstract: A single-hop wireless sensor network for distributed detection has been considered in the majority of the existing literature.
However, a wireless sensor network for an event detection application with cheap and short range sensors is likely to be amultihop
network. Here we consider a distributed detection problem in a multihop wireless sensor network with tree topology.We propose
an optimum multibit decision fusion rule derived from the previously known optimum likelihood ratio for a single-hop network
with star topology. Subsequently, we present an efficient multibit decision fusion rule for a multihop wireless sensor network
with tree topology. Through numerical results, the proposed scheme is shown to achieve a significant improvement in detection
accuracy over existing distributed detection schemes.
Abstract: In our work, we consider a querying application of a Multihop Cell phone Sensor Networks (MCpSN). It requires data to be sensed within a time window and further uploaded at the Querying Access Point within a time deadline. Considering a Random Waypoint distribution of cell phone users, we propose a novel, energy-efficient Spatio-Temporal Power Adaptive (STPA) protocol for this application. STPA is compared to purely spatially/temporally adaptive schemes through simulations.
Abstract: The late blight disease is the most common disease in potato, which is caused by the pathogen Phytopthora infestans. In this paper, a novel method to collect symptoms of the disease, as observed by the farmers, using a mobile phone application has been presented. A cumulative composite risk index (CCRI) obtained from more than one existing disease forecast models is validated from the actual late blight queries received from the farmers. The main contribution of the paper is a protocol that combines the symptoms based diagnostic approach along with the plant disease forecasting models resulting in detection of Potato late blight with higher accuracy. This in turn reduces the disease risk along with avoiding the unnecessary application of fungicide.
Abstract: In this paper, the benefits of Information and Communication Technology (ICT) to
solve most of the critical problems faced by rural community are presented. Moreover, the problems faced by rural
community are aggravated because of literacy, economic condition, technological anxiety which in-turn restrain
them from using IT infrastructure, lack of connectivity to the sources of information and lack of social interaction.
The important areas that needs attention at rural locations are related to
farming, education, finance and health-care.
%We focus on various problems like yield maximization,
%plant disease detection and forecast, optimizing irrigation and providing agricultural advices, market information,
%financial assistance and education to the farmers.
We develop a mobile phone based agro advisory system (mKRISHI) which serves as a unified solution to the problems
faced by rural community.
The proposed mKRISHI system is based on integrated use of technologies such as: sensor station,
mobile phone application, Internet, cellular network, and global positioning system.
The farmers can ask their queries to the domain experts using a texting-free, native language based,
voice enabled mKRISHI application on their mobile phone.
The experts have access to the sensor station parameters, farmer's profile, soil reports and farming history
for each farm to provide personalized advices to the farmers.
The field trials of mKRISHI system were carried out at four different locations in India for variety of crops.
With the experience of more than one year of operations, the excitement and adaptation of system is clearly visible
from increasing number of queries asked by the farmers. Further, the scalable architecture of mKRISHI facilitate to expand the
mKRISHI services both in terms of features as well as area covered
Abstract: In this paper, we consider moving event localization using data collected from a Multihop Cellular Sensor Network (MCSN). The main contribution of the paper is a novel structure- free Distributed Velocity Dependent (DVD) waiting time based protocol. We compare the performance of the proposed DVD protocol with that of a Centralized approach and the existing Randomized Waiting time (RW) protocol. Simulation results show that DVD exhibits a performance superior to RW with respect to center of event localization error and end-to-end delay. We also present simulation results on the the sensitivity analysis based comparison between DVD, RW and the Centralized scheme.
Abstract: The ubiquitous use of mobile phones motivates the idea of dasiaparticipatory sensingpsila with a cell-phone based sensor network. In our work, we consider a layered architecture for a query-based urban monitoring application using mobile phones. The key contribution of the paper is a Data-Aware Layered Waiting (DA-LW) time aggregation protocol in cell-phone based wireless sensor networks. To motivate the DA-LW protocol, we first develop a Cluster-Head (CH) based data aggregation protocol. The performance of the proposed protocols is evaluated in terms of energy, delay and resolution, which are primarily important for the monitoring application. Simulation results demonstrate the overall superiority in performance of the Data-Aware Layered Waiting algorithm over the Cluster-Head based algorithm.
Abstract: The problem of decision fusion for event detection in Wireless Sensor Networks is the prime focus of this paper. Our proposed algorithm focuses on single hop (star) and multihop (tree) topologies, which are commonly deployed wireless sensor network topologies. In order to minimize the overall energy consumption in the network, a transmission constraint of one-bit is imposed on each sensor node. This poses a challenging problem of designing a one-bit decision fusion rule at every fusion center, which improves the overall detection accuracy at the sink node. The absence of apriori knowledge of each sensor’s local performance indices, makes the existing optimum fusion rule infeasible. Moreover, in the absence of a training sequence of true event occurrences, existing Adaptive distributed detection techniques also become inapplicable. In this setup, the key contribution of this paper is a Least Mean Squares based Blind Adaptive Weighted Aggregation Scheme (Blind-AdWAS) for Wireless Sensor Networks with tree topology. We extend our earlier work (Jagyasi et al. in Proceedings of 11th international symposium on wireless personal multimedia communication, 2008) to include an analysis of the effect of Rayleigh flat fading channel on Blind-AdWAS in comparison with existing channel-aware optimum and sub- optimum aggregation schemes. Even in the absence of any channel knowledge or knowledge of performance indices, Blind-AdWAS demonstrates robustness in event detection performance.
Abstract: The problem of data aggregation for binary event detection using wireless sensor networks has been considered in the present work. We propose a novel multibit adaptive aggregation scheme (MAAS) which combines the merits of both multibit and adaptive aggregation schemes. Firstly, being adaptive, the proposed scheme does not require knowledge of the performance indices of sensor nodes as required by the existing optimum decision fusion rule. Therefore, in case of small variations in the topology or performance indices, the proposed scheme needs to just fine tune the weights starting from the previously adapted weights, instead of seeking new values of the parameters or recomputing the initial setup. Secondly, being a multibit aggregation scheme, the performance of the proposed MAAS is higher than the existing single-bit aggregation schemes at a cost of communicating only a few extra bits. This makes it suitable for event detection applications where detection accuracy is more important than the energy drained in communicating a few additional bits. Further, the performance of the proposed MAAS is shown to be consistently superior to single-bit schemes even in the presence of Rayleigh fading channel.
