Recursos de colección

ETD at Indian Institute of Science (2.987 recursos)

Repository of Theses and Dissertations of Indian Institute of Science, Bangalore, India. The repository has been developed to capture, disseminate and preserve research theses of Indian Institute of Science.

Centre for Electronic Design and Technology (cedt)

Mostrando recursos 1 - 20 de 53

  1. Resource Allocation in Wireless Networks for Secure Transmission and Utility Maximization

    Sarma, Siddhartha
    Resource allocation in wireless networks is one of the most studied class of problems. Generally, these problems are formulated as utility maximization problems under relevant constraints. The challenges posed by these problems vary widely depending on the nature of the utility function under consideration. Recently, the widespread prevalence of wireless devices prompted researchers and engineers to delve into the security issues of wireless communication. As compared to the wired medium, ensuring security for the wireless medium is more challenging mainly due to the broadcast nature of the transmission. But the ongoing research on physical layer security promises robust and reliable...

  2. Spatially Correlated Data Accuracy Estimation Models in Wireless Sensor Networks

    Karjee, Jyotirmoy
    One of the major applications of wireless sensor networks is to sense accurate and reliable data from the physical environment with or without a priori knowledge of data statistics. To extract accurate data from the physical environment, we investigate spatial data correlation among sensor nodes to develop data accuracy models. We propose three data accuracy models namely Estimated Data Accuracy (EDA) model, Cluster based Data Accuracy (CDA) model and Distributed Cluster based Data Accuracy (DCDA) model with a priori knowledge of data statistics. Due to the deployment of high density of sensor nodes, observed data are highly correlated among sensor...

  3. Wireless and Social Networks : Some Challenges and Insights

    Sunny, Albert
    Wireless networks have potential applications in wireless Internet connectivity, battlefields, disaster relief, and cyber-physical systems. While the nodes in these networks communicate with each other over the air, the challenges faced by and the subsequent design criteria of these networks are diverse. In this thesis, we study and discuss a few design requirements of these networks, such as efficient utilization of the network bandwidth in IEEE 802.11 infrastructure networks, evaluating utility of sensor node deployments, and security from eavesdroppers. The presence of infrastructure IEEE 802.11 based Wireless Local Area Networks (WLANs) allows mobile users to seamlessly transfer huge volumes of...

  4. Content Distribution in Social Groups

    Aggarwal, Saurabh
    We study Social Groups consisting of self-interested inter-connected nodes looking for common content. We can observe Social Groups in various socio-technological networks, such as Cellular Network assisted Device-to-Device communications, Cloud assisted Peer-to-Peer Networks, hybrid Peer-to-Peer Content Distribution Networks and Direct Connect Networks. Each node wants to acquire a universe of segments at least cost. Nodes can either access an expensive link to the content distributor for downloading data segments, or use the well-connected low cost inter-node network for exchanging segments among themselves. Activation of an inter-node link requires cooperation among the participating nodes and reduces the cost of downloading for...

  5. Capacity and Life Estimation of Flooded Lead Acid Batteries using Eddy Current Sensors

    Reddy, T Mohan
    Lead acid batteries are widely used in domestic, industrial and automotive applications. Even after lot of advancements in battery technologies, lead acid cells are still in use because of their high capacity and low cost. To use any battery effectively, first we should be able to identify the available capacity or State of Charge (SoC). There are many techniques available to measure SoC of a lead acid battery. One such unique method is to measure the capacity using eddy current sensors. This method is unique because it is non-obtrusive and online. Eddy current sensors (ECS) are wire wound inductors which...

  6. Capacity and Life Estimation of Flooded Lead Acid Batteries using Eddy Current Sensors

    Reddy, T Mohan
    Lead acid batteries are widely used in domestic, industrial and automotive applications. Even after lot of advancements in battery technologies, lead acid cells are still in use because of their high capacity and low cost. To use any battery effectively, first we should be able to identify the available capacity or State of Charge (SoC). There are many techniques available to measure SoC of a lead acid battery. One such unique method is to measure the capacity using eddy current sensors. This method is unique because it is non-obtrusive and online. Eddy current sensors (ECS) are wire wound inductors which...

  7. Architecture and Design of Wide Band Spectrum Sensing Receiver for Cognitive Radio Systems

    Adhikari, Bijaya
    To explore spectral opportunities in wideband regime for cognitive radio we need a wideband spectrum sensing receiver. Current wideband receiver architectures need wideband analog to digital converter (ADC) to sample wideband signal. As current state-of-art ADC has limitation in terms of power and sampling rate, we need to explore some alternative solutions. Compressive sampling (CS) data acquisition method is one of the solutions. Cognitive Radio signal, which is sparse in frequency domain can be sampled at Sub-Nyquist rate using low rate ADC. To relax the receiver complexity in terms of performance requirement we can use Modulated Wideband Converter (MWC) architecture,...

  8. Investigations on Hybrid Multilevel Inverters with a Single DC Supply for Zero and Reduced Common Mode Voltage Operation and Extended Linear Modulation Range Operation for Induction Motor Drives

    Arun Rahul, S
    Multilevel inverters play a major role in the modern day medium and high power energy conversion processes. The classic two level voltage source inverter generates PWM pole voltage output having two levels with strong fundamental component and harmonics centered around the switching frequency and its multiples. With higher switching frequency, its components can be easily filtered and results in better Total harmonic distortion (THD) output voltage and current. But with higher switching frequency, switching loss of power devices increases and electromagnetic interferences also increases. Also in two level inverter, pole voltage switches between zero and DC bus volt-age Vdc. This...

  9. Ballast-Free Variable-Speed Generation for Standalone and Grid-Connected Micro-Hydel Power Plants

    Joseph, Rex
    Concerns about climate change brought about by the increasing usage of fossil fuels has made it imperative to develop sustainable energy usage based on renewable sources. Micro-hydel plants are an important source of renewable energy that can be exploited to supply requirements of local loads in remote locations while operating as an isolated source, or the larger network when operating in grid connected mode. The focus of this research is to develop an alternative topology to the one currently in use in micro-hydel power plants. While existing plants are based on a ballast-controlled, fixed-speed, operator-supervised model, the proposed work introduces...

  10. Studies on Current Hysteresis Controllers and Low Order Harmonic Suppression Techniques for IM Drives with Dodecagoal Voltage Space Vectors

    Azeez, Najath Abdul
    Multilevel inverters are very popular for medium and high-voltage induction motor (IM) drive applications. They have superior performance compared to 2-level inverters such as reduced harmonic content in output voltage and current, lower common mode voltage and dv/dt, and lesser voltage stress on power switches. To get nearly sinusoidal current waveforms, the switching frequency of the conventional inverters have to be in¬creased. This will lead to higher switching losses and electromagnetic interference. The problem in using lower switching frequency is the introduction of low order harmonics in phase currents and undesirable torque ripple in the motor. The 5th and 7th...

  11. Studies on Current Hysteresis Controllers and Low Order Harmonic Suppression Techniques for IM Drives with Dodecagoal Voltage Space Vectors

    Azeez, Najath Abdul
    Multilevel inverters are very popular for medium and high-voltage induction motor (IM) drive applications. They have superior performance compared to 2-level inverters such as reduced harmonic content in output voltage and current, lower common mode voltage and dv/dt, and lesser voltage stress on power switches. To get nearly sinusoidal current waveforms, the switching frequency of the conventional inverters have to be in¬creased. This will lead to higher switching losses and electromagnetic interference. The problem in using lower switching frequency is the introduction of low order harmonics in phase currents and undesirable torque ripple in the motor. The 5th and 7th...

  12. Design, Development and Characterization of Variable Reluctance Ferrofluid Pump

    Hegde, Bharathkumar
    Ferrofluids are stable colloidal homogeneous mixtures of nano-size single-domain ferromag¬netic particles covered by surfactant layer, and suspended in a carrier fluid compatible with the surfactant. Physical properties of ferrofluid allows one to control it externally using magnetic field without being in direct contact with it. The thesis presents a novel mechanism to pump ferrofluid based on the principle of variable reluctance, in an external magnetic field. The static and dynamic pressure behavior of ferrofluid in a switched DC magnetic field gives an insight into the variable reluctance behavior of ferrofluid. A ferrofluid pump based on the prin¬ciple of variable reluctance...

  13. Design, Development and Characterization of Variable Reluctance Ferrofluid Pump

    Hegde, Bharathkumar
    Ferrofluids are stable colloidal homogeneous mixtures of nano-size single-domain ferromag¬netic particles covered by surfactant layer, and suspended in a carrier fluid compatible with the surfactant. Physical properties of ferrofluid allows one to control it externally using magnetic field without being in direct contact with it. The thesis presents a novel mechanism to pump ferrofluid based on the principle of variable reluctance, in an external magnetic field. The static and dynamic pressure behavior of ferrofluid in a switched DC magnetic field gives an insight into the variable reluctance behavior of ferrofluid. A ferrofluid pump based on the prin¬ciple of variable reluctance...

  14. Multilevel Dodecagonal Space Vector Structures and Modulation Schemes with Hybrid Topologies for Variable Speed AC Drives

    Kaarthik, R Sudharshan
    MULTILEVEL inverters are the preferred choice of converters for electronic power conversion for high power applications. They are gaining popularity in variety of industrial applications including electric motor drives, transportation, energy management, transmission and distribution of power. A large portion of energy conversion systems comprises of multilevel inverter fed induction motor drives. The multilevel inverters are ideal for such applications, since the switching frequency of the devices can be kept low. In conventional two level inverters, to get nearly sinusoidal phase current waveform, the switching frequency of the inverter is increased and the harmonics in the currents are pushed higher...

  15. Multilevel Dodecagonal Space Vector Structures and Modulation Schemes with Hybrid Topologies for Variable Speed AC Drives

    Kaarthik, R Sudharshan
    MULTILEVEL inverters are the preferred choice of converters for electronic power conversion for high power applications. They are gaining popularity in variety of industrial applications including electric motor drives, transportation, energy management, transmission and distribution of power. A large portion of energy conversion systems comprises of multilevel inverter fed induction motor drives. The multilevel inverters are ideal for such applications, since the switching frequency of the devices can be kept low. In conventional two level inverters, to get nearly sinusoidal phase current waveform, the switching frequency of the inverter is increased and the harmonics in the currents are pushed higher...

  16. A Study of Experience Mapping Based Predictive Controller as Applied to Switching Converters

    Nayak, Namratha
    Experience Mapping based Prediction Control (EMPC) is a new type of controller presented in literature, which is based on the concept of Human Motor Control (HMC). During the developmental phase, called the initial learning phase, the controller records the experience in a knowledge base, through online interactions with the system to be controlled. This knowledge base created using the experience maps is termed as Experience Mapped Knowledge Base (EMK). The controller envisages the development of EMK only through interaction with the system, without the need for knowledge of the detailed plant model. The EMPC controls the system through prediction of...

  17. Design and Optimization of Displacement Measurement Eddy Current Sensor for Mass Production

    Guganeswaran, S
    Eddy current (EC) based testing and measurement methods are well known in non-destructive testing (NDT) world. EC sensors are extensively studied and used for material health monitoring and its property measurement. Target displacement measurement is one of the well-known applications of EC method. The main advantage of EC sensor is its working capability in harsh environment like humidity, contamination etc. It is non-contact, rugged and requires less maintenance. The range and sensitivity of target displacement is mainly determined by the probe geometry and its construction method. Also displacement measurement depends upon geometry and electromagnetic (EM) properties of the target plate....

  18. Design and Optimization of Displacement Measurement Eddy Current Sensor for Mass Production

    Guganeswaran, S
    Eddy current (EC) based testing and measurement methods are well known in non-destructive testing (NDT) world. EC sensors are extensively studied and used for material health monitoring and its property measurement. Target displacement measurement is one of the well-known applications of EC method. The main advantage of EC sensor is its working capability in harsh environment like humidity, contamination etc. It is non-contact, rugged and requires less maintenance. The range and sensitivity of target displacement is mainly determined by the probe geometry and its construction method. Also displacement measurement depends upon geometry and electromagnetic (EM) properties of the target plate....

  19. Algorithm And Architecture Design for Real-time Face Recognition

    Mahale, Gopinath Vasanth
    Face recognition is a field of biometrics that deals with identification of subjects based on features present in the images of their faces. The factors that make face recognition popular and favorite as compared to other biometric methods are easier operation and ability to identify subjects without their knowledge. With these features, face recognition has become an integral part of the present day security systems, targeting a smart and secure world. There are various factors that de ne the performance of a face recognition system. The most important among them are recognition accuracy of algorithm used and time taken for...

  20. Algorithm And Architecture Design for Real-time Face Recognition

    Mahale, Gopinath Vasanth
    Face recognition is a field of biometrics that deals with identification of subjects based on features present in the images of their faces. The factors that make face recognition popular and favorite as compared to other biometric methods are easier operation and ability to identify subjects without their knowledge. With these features, face recognition has become an integral part of the present day security systems, targeting a smart and secure world. There are various factors that de ne the performance of a face recognition system. The most important among them are recognition accuracy of algorithm used and time taken for...

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