ETD at Indian Institute of Science
(529 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.
Mostrando recursos 1 - 18 de 18
1.
Checkpointing Algorithms for Parallel Computers - Kalaiselvi, S
Checkpointing is a technique widely used in parallel/distributed computers for rollback error recovery. Checkpointing is defined as the coordinated saving of process state information at specified time instances. Checkpoints help in restoring the computation from the latest saved state, in case of failure. In addition to fault recovery, checkpointing has applications in fault detection, distributed debugging and process migration.
Checkpointing in uniprocessor systems is easy due to the fact that there is a single clock and events occur with respect to this clock. There is a clear demarcation of events that happens before a checkpoint and events that happens after a...
2.
A Novel Chip Resistor Spacecloth For Radar Absorbing Materials - Sudhendra, Chandrika
Spacecloth design and development is vital and crucial in Radar Absorbing Materials (RAM) for achieving Low Observability in an Aircraft or an Unmanned Air Vehicle(UAV). The RAM design translates into the spacecloth design. The spacecloths form the constituent layers in a broadband Jaumann absorber in which case they have to be designed for various values of surface resistivity. The design specifications of spacecloth(s) in RAMS is well understood and documented in literature. But the design of spacecloth hitherto, has been the domain of materials' scientists wherein the specified properties of the spacecloth are achieved by an iterative, trial and error...
3.
CDMA Base Station Receive Co-Processor Architecture - Santhosam, Charles L
Third generation mobile communication systems promise a greater data rate and new services to the mobile subscribers. 3G systems support up to 2 Mbps of data rate to a fixed subscriber and 144 Kbps of data rate to a fully mobile subscriber. Code Division Multiple Access (CDMA) is the air interface access scheme widely used in all the 3G communication systems. This access scheme has many inherent advantages m terms of noise immunity, security, coherent combining of multi path signals etc. But all these advantages come at the expense of higher complexity of the receivers. The receivers form the major...
4.
One To Mant And Many To Many Collective Communication Operations On Grids - Gupta, Rakhi
Collective Communication Operations are widely used in MPI applications and play an important role in their performance. Hence, various projects have focused on optimization of collective communications for various kinds of parallel computing environments including LAN settings, heterogeneous networks and most recently Grid systems. The distinguishing factor of Grids from all the other environments is heterogeneity of hosts and network, and dynamically changing resource characteristics including load and availability.
The ?rst part of the thesis develops a solution for MPI broadcast (one-to-many) on Grids. Some current strategies take into consideration static information about network topology for determining an efficient broadcast...
5.
Power-Aware Compilation Techniques For Embedded Systems - Shyam, K
The demand for devices like Personal Digital Assistants (PDAs), Laptops, Smart Mobile
Phones, are at an all time high. As the demand for these devices increases, so is the push to provide sophisticated functionalities in these devices. However energy consumption has become a major constraint in providing increased functionality for these devices. A majority of the applications meant for these devices are rich with multimedia content.
In this thesis, we propose two approaches for compiler directed energy reduction, one
targeting the memory subsystem and another the processor.
The ?rst technique is a compiler directed optimization technique that reduces the
energy consumption of the memory subsystem,...
6.
Performance Modeling And Evaluation Of Network Processors - Govind, S
In recent years there has been an exponential growth in Internet traffic resulting in increased network bandwidth requirements which, in turn, has led to stringent processing requirements on network layer devices like routers. Present backbone routers on OC 48 links (2.5Gbps) have to process four million minimum-sized packets per second. Further, the functionality supported in the network devices is also on the increase leading to programmable processors, such as Intel's IXP, Motorola's C5 and IBM's.NP. These processors support multiple processors and multiple threads to exploit packet-level-parallelism inherent in network workloads.
This thesis studies the performance of network processors. We develop a...
7.
Applications Of Machine Learning To Anomaly Based Intrusion Detection - Phani, B
This thesis concerns anomaly detection as a mechanism for intrusion detection in a machine learning framework, using two kinds of audit data : system call traces and Unix shell command traces. Anomaly detection systems model the problem of intrusion detection as a problem of self-nonself discrimination problem. To be able to use machine learning algorithms for anomaly detection, precise definitions of two aspects namely, the learning model and the dissimilarity measure are required. The audit data considered in this thesis is intrinsically sequential. Thus the dissimilarity measure must be able to extract the temporal information in the data which in...
8.
A Systematic Approach To Synthesis Of Verification Test-Suites For Modular SoC Designs - Surendran, Sudhakar
SoCs (System on Chips) are complex designs with heterogeneous modules (CPU, memory, etc.) integrated in them. Verification is one of the important stages in designing an SoC. Verification is the process of checking if the transformation from architectural specification to design implementation is correct. Verification involves creating the following components: (i) a testplan that identifies the conditions to be verified, (ii) a testcase that generates the stimuli to verify the conditions identified, and (iii) a test-bench that applies the stimuli and monitors the output from the design.
Verification consumes upto 70% of the total design time. This is largely due...
9.
Information Theoretic Approach To Extractive Text Summarization - Ravindra, G
Automatic text summarization techniques, which can reduce a source text to a summary text by content generalization or selection have assumed signifi- cance in recent times due to the ever expanding information explosion created by the World Wide Web. Summaries generated by generalization of information are called abstracts and those generated by selection of portions of text (sentences, phrases etc.) are called extracts. Further, summaries could for each document separately or multiple documents could be summarized together to produce a single summary. The challenges in making machines generate extracts or abstracts are primarily due to the lack of understanding of...
10.
Improving The Communication Performance Of I/O Intensive And Communication Intensive Application In Cluster Computer Systems - Kumar, V Santhosh
Cluster computer systems assembled from commodity off-the-shelf components have emerged as a viable and cost-effective alternative to high-end custom parallel computer systems.In this thesis, we investigate how scalable performance can be achieved for database systems on clusters. In this context we specfically considered database query processing for evaluation of botlenecks and suggest optimization techniques for obtaining scalable application performance.
First we systematically demonstrated that in a large cluster with high disk bandwidth, the processing capability and the I/O bus bandwidth are the two major performance bottlenecks in database systems. To identify and assess bottlenecks, we developed a Petri net model...
11.
Analysis And Predictions Of DNA Sequence Transformations On Grids - Joshi, Yadnyesh R
Phylogenetics is the study of evolution of organisms. Evolution occurs due to mutations of DNA sequences. The reasons behind these seemingly random mutations are largely unknown. There are many algorithms that build phylogenetic trees from DNA sequences. However, there are certain uncertainties associated with these phylogenetic trees. Fine level analysis of these phylogenetic trees is both important and interesting for evolutionary biologists. In this thesis, we try to model evolutions of DNA sequences using Cellular Automata and resolve the uncertainties associated with the phylogenetic trees. In particular, we determine the effect of neighboring DNA base-pairs on the mutation of a...
12.
QoS Over Multihop Wireless Networks - Saxena, Tarun
The aim of this work is to understand the requirements behind Quality of Service (QoS) for Multihop Wireless Networks and evaluate the performance of different such strategies. This work starts by establishing the basis for requirement of QoS and evaluates different approaches for providing QoS. Bandwidth is selected as the most important resource amongst the resources identified for ensuring QoS. The problem is modeled as an optimization problem that tries to maximize the amount of bandwidth available in the system while providing bounds over the bandwidth available over a route. Other QoS parameters are bound by hard limits and are...
13.
Analysis Of Electromagnetic Pulse Simulators - Prakash, Rahul
Electromagnetic pulse simulators are essential for testing the ability of electronic devices to withstand high intensity electromagnetic ends. This work presents the analysis of various parallel plate transmission lines used in electromagnetic pulse simulators. Numerical techniques are developed to obtain the characteristic impedance, field map, and cut-infrequencies for the higher order modes of these transmission lines as exact analytical methods are not available for the determination of these quantities. The field map and characteristic impedance are computed using both finite element method (FEM) and boundary element method (BEM). Cut-off frequencies of the higher order modes are computed using FEM. The...
14.
Power Grid Analysis In VLSI Designs - Shah, Kalpesh
Power has become an important design closure parameter in today’s ultra low submicron
digital designs. The impact of the increase in power is multi-discipline to researchers ranging from power supply design, power converters or voltage regulators design, system, board and package thermal analysis, power grid design and signal integrity analysis to minimizing power itself. This work focuses on challenges arising due to increase in power to power grid design and analysis.
Challenges arising due to lower geometries and higher power are very well researched topics and there is still lot of scope to continue work. Traditionally, designs go through average IR...
15.
Reduction Of Query Optimizer Plan Diagrams - Darera, Pooja N
Modern database systems use a query optimizer to identify the most efficient strategy, called "plan", to execute declarative SQL queries. Optimization is a mandatory exercise since the difference between the cost of best plan and a random choice could be in orders of magnitude. The role of query optimization is especially critical for the decision support queries featured in data warehousing and data mining applications.
For a query on a given database and system configuration, the optimizer's plan choice is primarily a function of the selectivities of the base relations participating in the query. A pictorial enumeration of the execution...
16.
On The Issues Of Supporting On-Demand Streaming Application Over Peer-to-Peer Networks - Kalapriya, K
Bandwidth and resource constraints at the server side is a limitation for deployment of streaming media applications. Resource constraints at the server side often leads to saturation of resources during sudden increase in requests. End System Multicast (ESM) is used to overcome the problem of resource saturation. Resources such as storage, bandwidth available at the end systems are utilized to deliver streaming media. In ESM, the end-systems (also known as peers) form a network which is commonly known as Peer-to-Peer (P2P) network. These peers that receive the stream in turn act as routable components and forward the stream to other...
17.
Acoustic Source Localization Using Time Delay Estimation - Tellakula, Ashok Kumar
The angular location of an acoustic source can be estimated by measuring an acoustic direction of incidence based solely on the noise produced by the source. Methods for determining the direction of incidence based on sound intensity, the phase of cross-spectral functions, and cross-correlation functions are available. In this current work, we implement Dominant Frequency SElection (DFSE) algorithm. Direction of arrival (DOA) estimation usingmicrophone arrays is to use the phase information present in signals from microphones that are spatially separated. DFSE uses the phase difference between the Fourier transformedsignals to estimate the direction ofarrival (DOA)and is implemented using a three-element...
18.
Visibility Visualization And Haptic Path Exploration - Manohar, B S
We propose a real-time system to visualize multi-viewpoint visibility information for terrains, supporting flight path optimization for view coverage or vehicle exposure to ground. A volume rendered display and a haptic interface assist the user in selecting, assessing, and refining the computed flight path. We construct a three-dimensional scalar field representing the visibility of a point above the terrain, describe an efficient algorithm to compute visibility, and develop visual and haptic schemes to interact with the visibility field. Given the origin and destination, the desired flight path is computed using an efficient simulation of an articulated rope under the influence...
1.
