Theses and Dissertations
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Item Open Access Study of communication schemes for multiple neural processing nodes(Dhirubhai Ambani Institute of Information and Communication Technology, 2015) Mehta, Nilay V.; Mazad, ZaveriOver the past few years variety of hardware for implementing Artificial Neural Networks (ANN) has been designed. The most basic approach to speed up any ANN algorithm, is to parallelize processing. However, the existing wired strategies are not easily scalable and are also expensive. This thesis aims to provide low cost, easily scalable architecture for implementation of ANN, targeted for microcontrollers and FPGA architectures. With wired strategies, it is difficult to have scalable architecture with multiple Processing Nodes (PNs). Scalability of the same architecture can be improved by enabling wireless communication between the PNs. In this thesis, different strategies for implementation ofANNhave been analyzed, which considers two different types of PNs (Arduino R and Spartan3E R ) and various communication strategies (I2C with different speeds, Zigbee beacon enabled, Zigbee Non-beacon enabled, Zigbee GTS mode and TDMA scheme). Comparison of all these communication protocols have been carried out in terms of performance (speed) and energy. In this thesis, Nearest-Neighbour-Mesh (NNM) structure for the implementation is considered, where an application consists of 1024 neurons and 1024 synapses per neuron. The analysis has been carried out by varying number of PNs available for implementing this application. For simulation of all the wireless strategies, NS2 (Network Simulator) is used. For estimating computation time for Arduino and Spartan3E, Arduino software (Arduino 1.6.2) and Xilinx ISE Design Suite 14.7 R is used, respectively.Item Open Access Precision agriculture using wireless sensor network(Dhirubhai Ambani Institute of Information and Communication Technology, 2015) Joshi, Nikita Rajeshbhai; Shrivastava, SanjayFarming practices should evolve with the rapid increase in population. Recent growth in wireless sensor network (WSN) has the capability to meet this objective. Better quality in crop production can be achieved using real-time data collected through WSN. Also, greenhouse allows farming in a controlled environment. Hence, a combination of WSN and greenhouse gives better quality crop yield. Greenhouse requires climate control and fertigation management. Fertigation is a combination of irrigation and fertilization. Existing architectures for greenhouse management collect data of various parameters using sensor nodes and control values of parameters using actuators. These architectures have very limited capability to handle faults in sensors and actuators. Deployment of sensor nodes in these architectures is crop dependent. Therefore, while changing crops, modifications in the location of sensor node is needed and details of this modification should be entered manually in the database. Thus, they are not flexible architectures. In our work, a WSN based architecture for controlled environment like greenhouse is designed. This architecture provides for actuator control using crop requirements stored in the database. The architecture provides for deployment strategies for sensor nodes and actuators using the details about bed size, crop requirements etc. Localization algorithm is used to find the exact location of the sensor node. The architecture is flexible such that whenever location of sensors nodes needs to be changed, location of sensor nodes will be automatically detected using the localization algorithm. We have designed an algorithm to detect faults in sensor nodes and actuators. These faults are isolated or reported to the user. The architecture provides for network management strategies to control energy consumption of sensor nodes which eventually helps in increasing network lifetime. WSN algorithms for sleep scheduling and localization are used to support these features.We designed a system for a specific group of crops namely tomato, capsicum and cucumber using the architecture. This system is simulated in NS2 and it is verified that system is working as expected.Item Open Access Design of cutom wireless protocol for signal transmission inside space equipment(Dhirubhai Ambani Institute of Information and Communication Technology, 2014) Sanghani, Hardik Jayesh; Dubey, RahulThere are many sensors and devices inside the satellite. All these devices need to communicate with each other, those devices can be sensor nodes or control device. According to current technology communication between different sensor nodes inside the satellite is wired, which adds the weight of the harness cable. It will be reliable if the communication between them is made wireless. Protocol satisfying communication standards at low data rate and short range wireless networking must be developed. Protocol which is suitable to meet our requirements is available in the market in commercial packages, but the commercial standard devices cannot provide the efficient functionality in space as they are not resistant to the various radiation effects taking place in space. So our aim is to design a protocol in hardware description languages which can be embedded in radiation resistant series of space Grade FPGA. The baseband transceiver proposed in this thesis uses OQPSK modulation, Pseudo noise spread spectrum is used for coding and sinusoidal pulse shaping having theoretical bandwidth efficiency of 2bits/Hz same as QPSK and OQPSK is used for baseband processing. The transceiver is initially simulated in MATLAB Simulink and then in Verilog HDL by the MODELSIM simulator.Item Open Access Modeling and detecting attacks against key agreement protocols(Dhirubhai Ambani Institute of Information and Communication Technology, 2012) Yadav, Anshu; Mathuria, Anish M.Key agreement protocols establish a shared secret key between two or more communicating parties willing to exchange data over insecure channels using symmetric key cryptography. Based on the number of members involved in the communication these protocols can be classied as a two party or group key agreement protocols. Various formal methods are available in the literature to analyze the security of such protocols. This helps in establishing the validity of any attacks, if found, or to prove the security of the protocols under given adversarial assumptions. In this thesis we analyze the security of several existing two party and group key agreement protocols. We used provable security models like eCK'08 and enhanced eCK and the DS model given as an algebraic approach by Delicata and Schneider to analyze a class of DH based key agreement protocols. The distinguishing feature of key agreement protocols from key transport protocols is that the former aims to ensure the contribution of all the honest participants so that no one can predetermine the key. In a poorly designed protocol, an insider adversary can control the key in different forms as dened by Pieprzyk and Wang. This type of attack is termed as key control. We also dene ephemeral key control w.r.t. dishonest insider where it is assumed that the adversary also knows the ephemeral secret of the victim honest participants. This assumption is based on several advanced attributes that assume ephemeral leakage. We analyze this attack on MTI protocols using DS model. We have shown weakness in some provably secure two party implicitly authenticated protocols and modeled the attacks in provable security model. We also analyzed key control in some group key agreement protocols. We have used the DS model to formally derive an attack shown by Pieprzyk on Burmester-Desmedt protocol and have also proposed attacks on static version of the group key agreement protocol proposed by Dutta and Barua.Item Open Access Analysis of address allocation protocols for mobile ad hoc networks(Dhirubhai Ambani Institute of Information and Communication Technology, 2011) Sati, Mohit; Srivastava, Sanjay; Divakaran, SrikrishnanIn almost all networks, it is necessary to have a unique identifier for each node. This identifier is used to find out route locating a particular node. So an address is must for any node for unicast communication. Addresses can be preconfigured manually or can be assigned dynamically using a server (e.g. DHCP server). Manual configuration of ad hoc network is not possible for large scale networks. And setting up a server is not possible due to lack of infrastructure in Ad Hoc Networks. So it is necessary to have a mechanism by which we can allocate addresses to the nodes dynamically without any prior setup. Lack of infrastructure and mobility of nodes makes address allocation a challenging task in MANET. We present worst case message complexity analysis of a number of proposed address allocation protocols, which can be useful for estimating upper bounds for overhead and latency involved in address allocation as well as partitioning and merging. We also show that the worst case analysis is not a useful indicator of real world performance of the protocols. Buddy approach [5] is one of the many proposed approaches for address allocation. We model DPDA (A Distributed Protocol for Dynamic Address assignment in mobile ado networks)[6], a protocol based on buddy approach, to estimate the overhead involved in address allocation. We conduct simulations in NS-2 and compare with analytical results to validate our model. We perform simplified simulations using Python script which also validates the proposed model. We also do a simulation based comparison of MANETconf (MANET configuration) [8] and DPDA[6] in term of overhead and latency in address allocation, which shows that DPDA causes lower communication overhead and latency than Manetconf.Item Open Access Effect of location inaccuracy on deterministic coverage and connectivity protocol in wireless sensor network(Dhirubhai Ambani Institute of Information and Communication Technology, 2011) Jain, Poonam; Srivastava, SanjaySensor networks have a wide range of potential, practical and useful applications. Energy saving is one critical issue for sensor networks since most sensors are equipped with non rechargeable batteries that have limited lifetime. Many of the current literature of Energy efficient scheduling protocols assumed that sensing range of a sensor node is always uniform in all directions (unitdisc model). Unfortunately, this is not appropriate for the realistic sensing model, as the sensing capabilities of networked sensors are affected by environmental factors. The other issue is that most of the protocol used the location information of sensors for accurate data analysis. GPS technology and localization algorithms provide location information. But these technologies do not give accurate information, there is some uncertainty or error is exist in location information. Most of the protocols are location depended and will not work efficiently when inaccurate information is given. The main goal of this work is to analyze the performance of deterministic energy efficient scheduling protocol with location inaccuracy.Item Open Access CLAPDAWN: cross layer architecture for protocol design in a wireless network(Dhirubhai Ambani Institute of Information and Communication Technology, 2011) Jardosh, Sunil; Ranjan, PrabhatArchitecture plays a key role in overall success of the network protocol stack. It is essential to have robust architecture for the complex system having multiple cross protocol interactions. In the literature more emphasis is given to the cross layer protocol design than the cross layer architecture. Cross Layer Architectures [1, 2, 3, 4] available in literature are not addressing the problems of cross layer interaction at their depth. Our work focuses on cross layer architecture design that supports multiple cross layer protocols and cross layer interactions. It addresses the problem of lack of support for multiple cross layer interactions, feedback loops, a longer development time and smooth rollover from cross layer interaction. Our proposed Cross Layer Architecture for Protocol Design in A Wireless Network (CLAPDAWN) addresses these problems faced by many of the previously proposed architectures. We have worked on two critical problems of IEEE 802.15.4 based event driven wireless sensor networks: topology control problem and prioritized event handling problem. The IEEE 802.15.4 standard configures network nodes as Reduced Function Devices (RFD) and Full Function Devices (FFD). In randomly deployed wireless sensor networks, the problem of configuring the network nodes as RFD or FFD, maintaining the network functionality is a topology control problem. To solve this, we have proposed a multipoint relay based Connected Dominating Set (CDS) construction algorithm. In literature the topology control problem has been solved by centralized [5, 6, 6] and distributed [7, 8, 9] approaches. Dynamic nature of wireless sensor network makes centralized approaches less applicable and distributed approaches have the problem of overlapping and redundant nodes in the generated CDS. In our work we have proposed ROOT-Initiative (ROOT-I) and ROOT-Ik topology control algorithms to construct oneconnected and k-connected networks respectively. Proposed algorithms control the overlapping and redundant nodes in the network. They reduce the number of active nodes in the network that helps in extending the network lifetime. Further, the tradeoff between energy consumption and fault tolerability is analyzed for k-connectedness. Our results show that in randomly deployed dense networks, the algorithm has better approximation ratio with acceptable time and message complexity. The solution for the prioritized event handling is based on IEEE 802.15.4 MAC scheduling and channel access mechanism. IEEE 802.15.4 has Guaranteed Time Slot(GTS)mechanism for guaranteed data delivery. The GTS mechanism is not ufficient to provide solutions for the critical event handling problem. It has problems of reservation delay and limited number of GTS slots. To handle critical events in IEEE 802.15.4 based networks, we have proposed Explicit Prioritized Channel Access Protocol(EPCAP) and Implicit Prioritized Channel Access Protocol(IPCAP) mechanisms. The proposed mechanisms achieve higher delivery ratio for important events with smaller delay. The IPCAP and EPCAP are modeled using Markov chain and M/G/c queuing model respectively and tested through simulation. In ROOT-I and ROOT-Ik, network layer and MAC layer communicate to decide the node type (RFD or FFD) and in EPCAP and IPCAP prioritized events are handled by MAC based on information provided by application layer. As mentioned above CLAPDAWN is designed to support cross layer interactions in the system. To provide proof of concept for the CLAPDAWN we have modeled ROOT-I, ROOT-Ik, EPCAP and IPCAP as cross layer interactions in CLAPDAWN and we discuss how various components of CLAPDAWN communicate to implement these protocols. Furthermore to provide comparative analysis we have implemented ECLAIR [3] cross layer architecture with the CLAPDAWN.We have implemented the complex video streaming cross layer protocol [10] on both the architectures and derived the performance results. To make more rigorous comparison of both the architectures we have implemented conflicting cross layer interactions in the system. Our results show that CLAPDAWN has relatively better performance results than the ECLAIR. That shows CLAPDAWN provides better and stable platform for cross layer protocol development.Item Open Access Testbed based experimental analysis of transport protocols over wireless ad hoc networks(Dhirubhai Ambani Institute of Information and Communication Technology, 2009) Shah, Harshil Anilkumar; Srivastava, SanjayAd hoc networks are networks with no infrastructure and self-organized in nature. ad hoc networks allow nodes to form network when they come into range of each other provided nodes are configured in ad hoc mode. But these types of network are challenges like high bit error rates, route failures due to mobility, high noise, signal fading and low speed etc. to deal with. Due to this, protocols which are widely used in traditional wired networks may not perform well in MANETs. lower layers like MAC and network layer are either completely changed like 802.11 instead of 802.3 at MAC layer and introducing reactive routing protocols instead of only proactive routing at network layer or significant improvement schemes have been proposed for wireless networks in the existing legacy wired network protocols. But transport layer in MANET is mostly similar to wired networks except some improvements like TCP-ELFN and TCP-Feedback and new transport protocols like Ad hoc-TCP (ATCP), Transport Protocol for Ad hoc networks (TPA) and Ad-hoc Transport Pro- tool (ATP).performance degradation of TCP over wireless links is mainly due to wireless characteristics, TCP features like self-clocking, loss based congestion control, coupling of congestion and reliability, slow start. Several studies have been carried out to evaluate performance of TCP over MANETs but most of them are simulation based studies. But as simulation scenarios can not model exactly the unpredictable nature of wireless environment, we have decided to analyze performance of trans- port protocols over experimental test bed which can be more accurate evaluation of protocols in real-life situation. Performance of 2 transport protocols is analyzed.Item Open Access Cache performance evaluation in DSR protocol through cross-layering for mobile ad hoc networks(Dhirubhai Ambani Institute of Information and Communication Technology, 2009) Sharma, Kapil; Sunitha, V.Wireless mobile ad-hoc networks are being actively studied by many researchers these days. These networks are suitable to be used in various situations because of (i) their infrastructure-less property and (ii) the mobility of the nodes of the network. However, it is these features which give rice to problems in study of such networks. Further, routing is one of the basic issues in any network design. Inclusion of moving capability to the nodes, make the routing problem more complicated. One is always interested in increasing the throughput and reducing overhead while at the same time solving the issues related to routing. DSR is a protocol that is extensively used for routing in such networks. Cache management and route caching play a significant role in using DSR successively to attain the best behavior for these networks. This thesis looks at and suggests some methods for route caching in DSR.Item Open Access Cooperation enforcement mechanisms in wireless adhoc networks(Dhirubhai Ambani Institute of Information and Communication Technology, 2009) Chaturvedi, Manish Shivshankar; Srivastava, SanjayWireless adhoc networks are autonomous, infrastrutureless networks where there are no dedicated routers or base stations and nodes are expected to cooperate in Wireless performing routing duties to keep network connected. Cooperation can be assumed if all nodes belong to single authority (e.g. military service or disaster management). But in applications where nodes do not belong to single authority and have limited resources (energy of battery driven devices), like pervasive computing or ubiquitous computing environment, one can not deny possibility of node selfishness. Also as there is no central authority to control node behavior, one can not deny possibility of node maliciousness. Many cooperation enforcement schemes are proposed in literature, and every scheme is shown to perform better under its own set of assumptions. These assumptions are different for different schemes. So, we aim at defining common set of assumptions and comparing selected schemes on this common ground with respect to packet delivery ratio, energy consumption, routing and other control overhead. We find that with the traffic scenario where nodes do not need services of one another at the same time, the cooperation schemes are not effective in dealing with node selfish ness. We also find that, while dealing with malicious nodes, all cooperation schemes perform better than Dynamic Source Routing(DSR) protocol in improving packet de- livery ratio(PDR), but this improvement comes at the cost of significant increase in routing control packets overhead and energy consumption of cooperation enforcement schemes is higher than that of DSR. Also they fail in punishing misbehaving nodes and the PDR of malicious nodes is comparable to that of good nodes.