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edition: 2021-22 Aktu B.tech semester 5 Branch :IT 

The class $(r,2)$-CSP, or simply Max 2-CSP, consists of constraint satisfaction problems with at most two $r$-valued variables per clause. For instances with $n$ variables and $m$ binary clauses, we present an $O(n r^{5+19m/100})$-time algorithm which is the fastest polynomial-space algorithm for many problems in the class, including Max Cut. The method also proves a treewidth bound $\tw(G) \leq (13/75+o(1))m$, which gives a faster Max 2-CSP algorithm that uses exponential space: running in time $\Ostar{2^{(13/75+o(1))m}}$, this is fastest for most problems in Max 2-CSP. Parametrizing in terms of $n$ rather than $m$, for graphs of average degree $d$ we show a simple algorithm running time $\Ostar{2^{(1-\frac{2}{d+1})n}}$, the fastest polynomial-space algorithm known. In combination with ``Polynomial CSPs'' introduced in a companion paper, these algorithms also allow (with an additional polynomial-factor overhead in space and time) counting and sampling, and the solution of problems like Max Bisection that escape the usual CSP framework. Linear programming is key to the design as well as the analysis of the algorithms.

Many applications -- from planning and scheduling to problems in molecular biology -- rely heavily on a temporal reasoning component. In this paper, we discuss the design and empirical analysis of algorithms for a temporal reasoning system based on Allen's influential interval-based framework for representing temporal information. At the core of the system are algorithms for determining whether the temporal information is consistent, and, if so, finding one or more scenarios that are consistent with the temporal information. Two important algorithms for these tasks are a path consistency algorithm and a backtracking algorithm. For the path consistency algorithm, we develop techniques that can result in up to a ten-fold speedup over an already highly optimized implementation. For the backtracking algorithm, we develop variable and value ordering heuristics that are shown empirically to dramatically improve the performance of the algorithm. As well, we show that a previously suggested reformulation of the backtracking search problem can reduce the time and space requirements of the backtracking search. Taken together, the techniques we develop allow a temporal reasoning component to solve problems that are of practical size.

ADALAB

ADALAB

The objective of this research is to develop efficient parallel algorithms for a variety of problems and to analyze the scalability of new and existing parallel algorithms. Scalability analysis is an important tool used for predicting the performance of an algorithm-architecture combination when one or more of the hardware related parameters (interconnection network, speed of processors, speed of communication channels, number of processors) are changed. The problems studied as a part of this project come from diverse domains such as solution of differential equations, discrete optimization, neural network based learning, sorting and graph algorithms. In particular, we have studied parallel algorithms for solving linear systems using the preconditioned conjugate gradient method, partitioning of finite element meshes, balancing load in unstructured tree search arising in discrete optimization, the backpropagation neural network learning algorithm, dynamic programming, fast fourier transform, sorting, shortest-path computation for graphs, robot motion planning, and matrix multiplication. Parallel algorithms, Scalability analysis, Isoefficiency.

In this thesis, the advantages of three different maximum power point tracking (MPPT) algorithm are investigated. By simulation, the performance and efficiency of these algorithms was analyzed. By using MATLAB's SimPowerSystems block set, we created the model comprised of a Kyocera KD135GX-LP solar panel powering a buck converter controlled by the MPPT algorithms driving a resistive load. The main objective was to track the maximum power point (MPP) of the solar array by modulating the buck converter's duty cycle, thereby, optimizing the power output of the panel. The three algorithms observed performance was on par with other real world tests of these algorithms as seen in other published work. The Perturb and Observe (P&O) algorithm performed with a higher overall efficiency and was able to track the MPP quickly, while the Incremental Conductance (InC) algorithm had similar performance but requires more intensive calculations. The analysis of these algorithms led to a greater understanding of where the inefficiencies of this type of system are located, allowing improvement in future work on this subject.

Lectures from the National Programme on Technology Enhanced Learning - Computer Science and Engineering - Design and Analysis of Algorithms

In this paper, we present a probabilistic analysis of iterative node-based verification-based (NB-VB) recovery algorithms over irregular graphs in the context of compressed sensing. Verification-based algorithms are particularly interesting due to their low complexity (linear in the signal dimension $n$). The analysis predicts the average fraction of unverified signal elements at each iteration $\ell$ where the average is taken over the ensembles of input signals and sensing matrices. The analysis is asymptotic ($n \rightarrow \infty$) and is similar in nature to the well-known density evolution technique commonly used to analyze iterative decoding algorithms. Compared to the existing technique for the analysis of NB-VB algorithms, which is based on numerically solving a large system of coupled differential equations, the proposed method is much simpler and more accurate. This allows us to design irregular sensing graphs for such recovery algorithms. The designed irregular graphs outperform the corresponding regular graphs substantially. For example, for the same recovery complexity per iteration, we design irregular graphs that can recover up to about 40% more non-zero signal elements compared to the regular graphs. Simulation results are also provided which demonstrate that the proposed asymptotic analysis matches the performance of recovery algorithms for large but finite values of $n$.

In this paper, we present a probabilistic analysis of iterative node-based verification-based (NB-VB) recovery algorithms over irregular graphs in the context of compressed sensing. Verification-based algorithms are particularly interesting due to their low complexity (linear in the signal dimension $n$). The analysis predicts the average fraction of unverified signal elements at each iteration $\ell$ where the average is taken over the ensembles of input signals and sensing matrices. The analysis is asymptotic ($n \rightarrow \infty$) and is similar in nature to the well-known density evolution technique commonly used to analyze iterative decoding algorithms. Compared to the existing technique for the analysis of NB-VB algorithms, which is based on numerically solving a large system of coupled differential equations, the proposed method is much simpler and more accurate. This allows us to design irregular sensing graphs for such recovery algorithms. The designed irregular graphs outperform the corresponding regular graphs substantially. For example, for the same recovery complexity per iteration, we design irregular graphs that can recover up to about 40% more non-zero signal elements compared to the regular graphs. Simulation results are also provided which demonstrate that the proposed asymptotic analysis matches the performance of recovery algorithms for large but finite values of $n$.

This thesis explores various theoretical aspects of machine learning with particular emphasis on techniques for designing and analyzing computationally efficient learning algorithms. Many of the results in this thesis are concerned with a model of concept learning proposed by Valiant. The thesis begins in Chapter 2 with a proof that any 'weak' learning algorithm in this model that performs slightly better than random guessing can be converted into one whose error can be made arbitrarily small. Several interesting consequences of this result are also described. Chapter 3 next explores in detail a simple but powerful technique for discovering the structure of an unknown read-once formula from random examples. An especially nice feature of this technique is its powerful resistance to noise. Chapter 4 considers a realistic extension of the PAC model to concepts that may exhibit uncertain or probabilistic behavior. A range of techniques are explored for designing efficient algorithms for learning such probabilistic concepts. In the last chapter, we present new algorithms for inferring an unknown finite-state automation from its input-output behavior. This problem is motivated by that faced by a robot in unfamiliar surroundings who must, through experimentation, discover the structure of its environment.

The primary objective of this project is to design, analyze, and test new autopilot algorithms for trajectory tracking control of dual range missiles. The main contributions of this project can be summarized as follows. First, a low-order memory-based control method was developed. This method is based on observing and generalizing past system responses and control experience. It does not demand detailed information about the system dynamics. Second, the memory-based method is integrated with a partial inverse dynamics control and applied to achieve missile orientation tracking in the presence of actuator dynamics and aerodynamics. It is shown that this method is effective in dealing with system nonlinearities and uncertainties due to varying flight conditions. The method is also extended to position/orientation tracking. Finally, the developed autopilot algorithms were tested via computer simulation.

The primary objective of this project is to design, analyze, and test new autopilot algorithms for trajectory tracking control of dual range missiles. The main contributions of this project can be summarized as follows. First, a low-order memory-based control method was developed. This method is based on observing and generalizing past system responses and control experience. It does not demand detailed information about the system dynamics. Second, the memory-based method is integrated with a partial inverse dynamics control and applied to achieve missile orientation tracking in the presence of actuator dynamics and aerodynamics. It is shown that this method is effective in dealing with system nonlinearities and uncertainties due to varying flight conditions. The method is also extended to position/orientation tracking. Finally, the developed autopilot algorithms were tested via computer simulation.

ADALAB

To address the data review burden and improve the reliability of the ultrasonic inspection of large composite structures, automated data analysis (ADA) algorithms have been developed to make calls on indications that satisfy the detection criteria and minimize false calls. The original design followed standard procedures for analyzing signals for time-of-flight indications and backwall amplitude dropout. However, certain complex panels with varying shape, ply drops and the presence of bonds can complicate this interpretation process. In this paper, enhancements to the automated data analysis algorithms are introduced to address these challenges. To estimate the thickness of the part and presence of bonds without prior information, an algorithm tracks potential backwall or bond-line signals, and evaluates a combination of spatial, amplitude, and time-of-flight metrics to identify bonded sections. Once part boundaries, thickness transitions and bonded regions are identified, feature extraction algorithms are applied to multiple sets of through-thickness and backwall C-scan images.

Design and Analysis of Algorithms. Computer Science course material

Design and Analysis of Algorithms. Computer Science course material

In many countries, the currently observable transformation of the power supply system from a centrally controlled system towards a complex "system of systems", comprising lots of autonomously interacting components, leads to a significant amount of research regarding novel control concepts. To facilitate the structured development of such approaches regarding the criticality of the targeted system, the research and development of a distributed control concept is demonstrated by employing an integrated methodology comprising both the Smart Grids Architecture Model framework (SGAM) and the Smart Grid Algorithm Engineering process model (SGAE). Along the way, a taxonomy of evaluation criteria and evaluation methods for such approaches is presented. For the whole paper, the Dynamic Virtual Power Plants business case (DVPP) serves as motivating example.

This paper presents reduced-rank linearly constrained minimum variance (LCMV) beamforming algorithms based on joint iterative optimization of filters. The proposed reduced-rank scheme is based on a constrained joint iterative optimization of filters according to the minimum variance criterion. The proposed optimization procedure adjusts the parameters of a projection matrix and an adaptive reducedrank filter that operates at the output of the bank of filters. We describe LCMV expressions for the design of the projection matrix and the reduced-rank filter. We then describe stochastic gradient and develop recursive least-squares adaptive algorithms for their efficient implementation along with automatic rank selection techniques. An analysis of the stability and the convergence properties of the proposed algorithms is presented and semi-analytical expressions are derived for predicting their mean squared error (MSE) performance. Simulations for a beamforming application show that the proposed scheme and algorithms outperform in convergence and tracking the existing full-rank and reduced-rank algorithms while requiring comparable complexity

This paper presents reduced-rank linearly constrained minimum variance (LCMV) beamforming algorithms based on joint iterative optimization of filters. The proposed reduced-rank scheme is based on a constrained joint iterative optimization of filters according to the minimum variance criterion. The proposed optimization procedure adjusts the parameters of a projection matrix and an adaptive reducedrank filter that operates at the output of the bank of filters. We describe LCMV expressions for the design of the projection matrix and the reduced-rank filter. We then describe stochastic gradient and develop recursive least-squares adaptive algorithms for their efficient implementation along with automatic rank selection techniques. An analysis of the stability and the convergence properties of the proposed algorithms is presented and semi-analytical expressions are derived for predicting their mean squared error (MSE) performance. Simulations for a beamforming application show that the proposed scheme and algorithms outperform in convergence and tracking the existing full-rank and reduced-rank algorithms while requiring comparable complexity

Subspace and Lanczos iterations have been developed, well documented, and widely accepted as efficient methods for obtaining p-lowest eigen-pair solutions of large-scale, practical engineering problems. The focus of this paper is to incorporate recent developments in vectorized sparse technologies in conjunction with Subspace and Lanczos iterative algorithms for computational enhancements. Numerical performance, in terms of accuracy and efficiency of the proposed sparse strategies for Subspace and Lanczos algorithm, is demonstrated by solving for the lowest frequencies and mode shapes of structural problems on the IBM-R6000/590 and SunSparc 20 workstations.

MIT Design and Analysis of Algorithms Prof. Erik Demaine Prof. Srini Devadas Prof. Nancy Lynch MIT Course Number 6.046J / 18.410J As Taught In Spring 2015 Level Undergraduate

The objective of this paper is to find an alternative to conventional method of concrete mix design. For finding the alternative, 4 machine learning algorithms viz. multi-variable linear regression, Support Vector Regression, Decision Tree Regression and Artificial Neural Network for designing concrete mix of desired properties. The multi-variable linear regression model is just a simplistic baseline model, support vector regression Artificial Neural Network model were made because past researchers worked heavily on them, Decision tree model was made by authors own intuition. Their results have been compared to find the best algorithm. Finally, we check if the best performing algorithm is accurate enough to replace the convention method. For this, we utilize the concrete mix designs done in lab for various on site designs. The models have been designed for both mixes types – with plasticizer and without plasticizer The paper presents detailed comparison of four models Based on the results obtained from the four models, the best one has been selected based on high accuracy and least computational cost. Each sample had 24 features initially, out of which, most significant features were chosen which were contributing towards prediction of a variable using f regression and p values and models were trained on those selected features. Based on the R squared value, best fitting models were selected among the four algorithms used. From the paper, the author(s) conclude that decision tree regression is best for calculating the amount of ingredients required with R squared values close to 0.8 for most of the models. DTR model is also computationally cheaper than ANN and future works with DTR in mix design is highly recommended in this paper.

The objective of this paper is to find an alternative to conventional method of concrete mix design. For finding the alternative, 4 machine learning algorithms viz. multi-variable linear regression, Support Vector Regression, Decision Tree Regression and Artificial Neural Network for designing concrete mix of desired properties. The multi-variable linear regression model is just a simplistic baseline model, support vector regression Artificial Neural Network model were made because past researchers worked heavily on them, Decision tree model was made by authors own intuition. Their results have been compared to find the best algorithm. Finally, we check if the best performing algorithm is accurate enough to replace the convention method. For this, we utilize the concrete mix designs done in lab for various on site designs. The models have been designed for both mixes types – with plasticizer and without plasticizer The paper presents detailed comparison of four models Based on the results obtained from the four models, the best one has been selected based on high accuracy and least computational cost. Each sample had 24 features initially, out of which, most significant features were chosen which were contributing towards prediction of a variable using f regression and p values and models were trained on those selected features. Based on the R squared value, best fitting models were selected among the four algorithms used. From the paper, the author(s) conclude that decision tree regression is best for calculating the amount of ingredients required with R squared values close to 0.8 for most of the models. DTR model is also computationally cheaper than ANN and future works with DTR in mix design is highly recommended in this paper.

A high performance, versatile, and reliable underwater communications capability is of strategic importance to the U.S. Navy. Operational scenarios involving the use, monitoring, and coordination of multiple undersea assets, both manned and unmanned and mobile and fixed, are significantly enhanced by the ability to communicate quickly, reliably, in a wide range of environmental conditions, and with minimal constraints on the actions of the platforms involved. The long-term goal of the effort in underwater acoustic communications is to integrate research in the areas of physical oceanography, ocean acoustics, signal processing, and communications theory to 1. develop a underwater communications capability that can be deployed on and used by a wide range of platforms with minimal required external infrastructure and which achieves reliable and high performance under a wide range of environmental and operational conditions, and 2. develop an communications performance prediction capability that enables commanders to reliably predict the performance of deployed communications systems as a function of environmental conditions and the location, velocity, and capabilities of the deployed assets.

DESIGN AND ANALYSIS OF ALGORITHMS 

DESIGN AND ANALYSIS OF ALGORITHMS 

This manuscript develops a new framework to analyze and design iterative optimization algorithms built on the notion of Integral Quadratic Constraints (IQC) from robust control theory. IQCs provide sufficient conditions for the stability of complicated interconnected systems, and these conditions can be checked by semidefinite programming. We discuss how to adapt IQC theory to study optimization algorithms, proving new inequalities about convex functions and providing a version of IQC theory adapted for use by optimization researchers. Using these inequalities, we derive numerical upper bounds on convergence rates for the gradient method, the heavy-ball method, Nesterov's accelerated method, and related variants by solving small, simple semidefinite programming problems. We also briefly show how these techniques can be used to search for optimization algorithms with desired performance characteristics, establishing a new methodology for algorithm design.

Combinatorial optimization is widely applied in a number of areas nowadays. Unfortunately, many combinatorial optimization problems are NP-hard which usually means that they are unsolvable in practice. However, it is often unnecessary to have an exact solution. In this case one may use heuristic approach to obtain a near-optimal solution in some reasonable time. We focus on two combinatorial optimization problems, namely the Generalized Traveling Salesman Problem and the Multidimensional Assignment Problem. The first problem is an important generalization of the Traveling Salesman Problem; the second one is a generalization of the Assignment Problem for an arbitrary number of dimensions. Both problems are NP-hard and have hosts of applications. In this work, we discuss different aspects of heuristics design and evaluation. A broad spectrum of related subjects, covered in this research, includes test bed generation and analysis, implementation and performance issues, local search neighborhoods and efficient exploration algorithms, metaheuristics design and population sizing in memetic algorithm. The most important results are obtained in the areas of local search and memetic algorithms for the considered problems. In both cases we have significantly advanced the existing knowledge on the local search neighborhoods and algorithms by systematizing and improving the previous results. We have proposed a number of efficient heuristics which dominate the existing algorithms in a wide range of time/quality requirements. Several new approaches, introduced in our memetic algorithms, make them the state-of-the-art metaheuristics for the corresponding problems. Population sizing is one of the most promising among these approaches; it is expected to be applicable to virtually any memetic algorithm.

View the complete course: http://ocw.mit.edu/6-046JS15 Instructors: Erik Demaine, Srinivas Devadas, Nancy Ann Lynch 6.046 introduces students to the design of computer algorithms, as well as analysis of sophisticated algorithms. License: Creative Commons BY-NC-SA More information at http://ocw.mit.edu/terms More courses at http://ocw.mit.edu

Subspace and Lanczos iterations have been developed, well documented, and widely accepted as efficient methods for obtaining p-lowest eigen-pair solutions of large-scale, practical engineering problems. The focus of this paper is to incorporate recent developments in vectorized sparse technologies in conjunction with Subspace and Lanczos iterative algorithms for computational enhancements. Numerical performance, in terms of accuracy and efficiency of the proposed sparse strategies for Subspace and Lanczos algorithm, is demonstrated by solving for the lowest frequencies and mode shapes of structural problems on the IBM-R6000/590 and SunSparc 20 workstations.

The article begins by examining the fundamentals of traditional deterministic design philosophy. The initial section outlines the concepts of failure criteria and limit state functions two traditional notions that are embedded in deterministic design philosophy. This is followed by a discussion regarding safety factors (a possible limit state function) and the common utilization of statistical concepts in deterministic engineering design approaches. Next the fundamental aspects of a probabilistic failure analysis are explored and it is shown that deterministic design concepts mentioned in the initial portion of the article are embedded in probabilistic design methods. For components fabricated from ceramic materials (and other similarly brittle materials) the probabilistic design approach yields the widely used Weibull analysis after suitable assumptions are incorporated. The authors point out that Weibull analysis provides the rare instance where closed form solutions are available for a probabilistic failure analysis. Since numerical methods are usually required to evaluate component reliabilities, a section on Monte Carlo methods is included to introduce the concept. The article concludes with a presentation of the technical aspects that support the numerical method known as fast probability integration (FPI). This includes a discussion of the Hasofer-Lind and Rackwitz-Fiessler approximations.

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The article begins by examining the fundamentals of traditional deterministic design philosophy. The initial section outlines the concepts of failure criteria and limit state functions two traditional notions that are embedded in deterministic design philosophy. This is followed by a discussion regarding safety factors (a possible limit state function) and the common utilization of statistical concepts in deterministic engineering design approaches. Next the fundamental aspects of a probabilistic failure analysis are explored and it is shown that deterministic design concepts mentioned in the initial portion of the article are embedded in probabilistic design methods. For components fabricated from ceramic materials (and other similarly brittle materials) the probabilistic design approach yields the widely used Weibull analysis after suitable assumptions are incorporated. The authors point out that Weibull analysis provides the rare instance where closed form solutions are available for a probabilistic failure analysis. Since numerical methods are usually required to evaluate component reliabilities, a section on Monte Carlo methods is included to introduce the concept. The article concludes with a presentation of the technical aspects that support the numerical method known as fast probability integration (FPI). This includes a discussion of the Hasofer-Lind and Rackwitz-Fiessler approximations.

CS Books

ADALABPDF

ADALABPDF

ADALABPDF

Several methods for modeling and analysis of parallel algorithms and architecture have been proposed in the recent years. These include recursion-type methods, like recursion equations, z-transform descriptions and 'do-loops' in high-level programming languages, and precedence-graph-type methods like data-flow graphs (marked graphs) and related Petri-net derived models. This paper presents a new methodology for modeling and analysis of parallel algorithms and architectures. This methodology provides a unified conceptual framework that clearly displays the key properties of parallel systems. This methodology is largely based upon the theory of directed graphs and can, therefore, be expressed both informally, in pictorial fashion, and formally, in the language of precedence relations and compositions of functions. This duality will, hopefully, help to bridge the gap between the two schools of research in this field.

Several methods for modeling and analysis of parallel algorithms and architecture have been proposed in the recent years. These include recursion-type methods, like recursion equations, z-transform descriptions and 'do-loops' in high-level programming languages, and precedence-graph-type methods like data-flow graphs (marked graphs) and related Petri-net derived models. This paper presents a new methodology for modeling and analysis of parallel algorithms and architectures. This methodology provides a unified conceptual framework that clearly displays the key properties of parallel systems. This methodology is largely based upon the theory of directed graphs and can, therefore, be expressed both informally, in pictorial fashion, and formally, in the language of precedence relations and compositions of functions. This duality will, hopefully, help to bridge the gap between the two schools of research in this field.

In this thesis, the advantages of three different maximum power point tracking (MPPT) algorithm are investigated. By simulation, the performance and efficiency of these algorithms was analyzed. By using MATLAB's SimPowerSystems block set, we created the model comprised of a Kyocera KD135GX-LP solar panel powering a buck converter controlled by the MPPT algorithms driving a resistive load. The main objective was to track the maximum power point (MPP) of the solar array by modulating the buck converter's duty cycle, thereby, optimizing the power output of the panel. The three algorithms observed performance was on par with other real world tests of these algorithms as seen in other published work. The Perturb and Observe (P&O) algorithm performed with a higher overall efficiency and was able to track the MPP quickly, while the Incremental Conductance (InC) algorithm had similar performance but requires more intensive calculations. The analysis of these algorithms led to a greater understanding of where the inefficiencies of this type of system are located, allowing improvement in future work on this subject.

The characteristic of an asynchronous multiprocessor is that it is composed of several processors capable of carrying out the execution of their own programs in a completely independent fashion. As a consequence, parallel algorithms for asynchronous multiprocessors present some unique aspects in both their design and their analysis. This thesis explores the issues raised by the design and the analysis of parallel algorithms for asynchronous multiprocessors and illustrates the various notions and concepts involved with these algorithms by considering problems in diverse areas. The thesis demonstrates that asynchronous multiprocessors can be used efficiently in different problem domains, provided that appropriate algorithms are used. It also illustrates various techniques useful in the analysis of such algorithms. As evidenced by a series of experimental results, the computation time required by a process to execute several instances of the same task on an asynchronous multiprocessor cannot be regarded as constant and is actually subject to important fluctuations. These fluctuations in computation times have a negative effect on the performance of parallel algorithms when several processes cooperating in the solution of a problem communicate extensively among themselves. In this case, when synchronization is used, it tends to introduce a prohibitive overhead which decreases the parallelism. On the other hand, an algorithm is presented to illustrate that the fluctuations are not always a negative factor but can also be utilized advantageously.

This paper traces the development of computational fluid dynamics as a tool for aircraft design. It addresses the requirements for effective industrial use, and trade-offs between modeling accuracy and computational costs. Essential elements of algorithm design are discussed in detail, together with a unified approach to the design of shock capturing schemes. Finally, the paper discusses the use of techniques drawn from control theory to determine optimal aerodynamic shapes. In the future multidisciplinary analysis and optimization should be combined to provide an integrated design environment.

Route assignment is one of the operational problems of communication network, and adaptive routing schemes are required to achieve real time performance. This thesis introduces, verifies and analyses two new distributed, shortest-path routing algorithms, which are called, Path-Finding Algorithm (PFA) and Loop-Free Path-Finding Algorithm (LPA). Both algorithms require each routing node to know only the distance and the second-to-last-hop (or predecessor) node to each destination. In addition to the above information, LPA uses an efficient inter-neighbor coordination mechanism spanning over a single hop. PFA reduces the formation of temporary loops significantly, while LPA achieves loop-freedom at every instant by eliminating temporary loops. The average performance of these two algorithms is compared with the Diffusing Update Algorithm (DUAL) and an ideal link state (ILS) using Dijkstra's shortest-path algorithm by simulation; this performance comparison is made in terms of time taken for convergence, number of packets exchanged and the total number of operations required for convergence by each of the algorithms. The simulations were performed using a C-based simulation tool called Drama, along with a network simulation library. The results indicated that the performance of PFA is comparable to that of DUAL and ILS and that a significant improvement in performance can be achieved with LPA over DUAL and ILS.

Route assignment is one of the operational problems of communication network, and adaptive routing schemes are required to achieve real time performance. This thesis introduces, verifies and analyses two new distributed, shortest-path routing algorithms, which are called, Path-Finding Algorithm (PFA) and Loop-Free Path-Finding Algorithm (LPA). Both algorithms require each routing node to know only the distance and the second-to-last-hop (or predecessor) node to each destination. In addition to the above information, LPA uses an efficient inter-neighbor coordination mechanism spanning over a single hop. PFA reduces the formation of temporary loops significantly, while LPA achieves loop-freedom at every instant by eliminating temporary loops. The average performance of these two algorithms is compared with the Diffusing Update Algorithm (DUAL) and an ideal link state (ILS) using Dijkstra's shortest-path algorithm by simulation; this performance comparison is made in terms of time taken for convergence, number of packets exchanged and the total number of operations required for convergence by each of the algorithms. The simulations were performed using a C-based simulation tool called Drama, along with a network simulation library. The results indicated that the performance of PFA is comparable to that of DUAL and ILS and that a significant improvement in performance can be achieved with LPA over DUAL and ILS.

Charlotte Turner Smith (1749 – 1806) was an English poet and novelist. She initiated a revival of the English sonnet, helped establish the conventions of Gothic fiction, and wrote political novels of sensibility.<br /><br />It was in 1784, in debtor's prison with her husband Benjamin, that she wrote and published her first work, Elegiac Sonnets. The work achieved instant success, allowing Charlotte to pay for their release from prison. Smith's sonnets helped initiate a revival of the form and granted an aura of respectability to her later novels.<br /><br />Stuart Curran, the editor of Smith's poems, has written that Smith is "the first poet in England whom in retrospect we would call Romantic". She helped shape the "patterns of thought and conventions of style" for the period. Romantic poet William Wordsworth was the most affected by her works. He said of Smith in the 1830s that she was "a lady to whom English verse is under greater obligations than are likely to be either acknowledged or remembered". By the second half of the nineteenth century, however, Smith was largely forgotten.

2Wealth of Nations, Book 1

By Adam Smith

An Inquiry into the Nature and Causes of the Wealth of Nations is the magnum opus of the Scottish economist Adam Smith, published on March 9, 1776 during the Scottish Enlightenment. It is a clearly written account of political economy at the dawn of the Industrial Revolution, and is widely considered to be the first modern work in the field of economics. (Summary from Wikipedia)

"How selfish soever man may be supposed, there are evidently some principles in his nature, which interest him in the fortunes of others, and render their happiness necessary to him, though he derives nothing from it, except the pleasure of seeing it." (from The Theory of Moral Sentiments)<br><br>Adam Smith considered his first major book, The Theory of Moral Sentiments, his most important work. Indeed, the tome was a wild success upon its publication, selling out immediately. It has not lost popularity since. In this legendary work, Smith discusses the nature of morality, and the motives behind and origins of these "sentiments." Originally published in 1759, this work provides the philosophical underpinnings for his later works, as well as elucidating the psychological and moral foundations of the workings of a complex society. Smith parses many important concepts in this book, with the central questions perhaps being: Where do our moral principles come from? Are they divine and inborn, reflection of man-made laws, or rational, based on their usefulness to society? Smith's answers to these questions and more, and his explanation of how such sentiments, however derived, influence society's self-coordination, have interested lay and scholar alike for hundreds of years. (summary written by Nikki Sullivan)<br /><br /> note: This is the First edition, the 6th edition was revised and extra material added.

A story for children about a little bear with no name, “there were not enough names to go round,” and his adventures in finding one. (Summary by Carolyn Frances)

<i>The Fairy Ring</i>, originally published in 1910, is a collection of 63 fairy tales from around the globe. It includes such well-known favorites as "History of Jack the Giant-Killer", "The Frog Prince","Rumpel-stilts-ken", and "Snow-white and Rose-red", among many others. Children of all ages will enjoy these stories. (Summary by Paul Williams)

6Wealth of Nations, Book 2 and 3

By Adam Smith

An Inquiry into the Nature and Causes of the Wealth of Nations is the magnum opus of the Scottish economist Adam Smith, published on March 9, 1776 during the Scottish Enlightenment. It is a clearly written account of political economy at the dawn of the Industrial Revolution, and is widely considered to be the first modern work in the field of economics. (from Wikipedia)

7Masters of Space

By Edward Everett Evans and E. E. Smith

The Masters had ruled all space with an unconquerable iron fist. But the Masters were gone. And this new, young race who came now to take their place--could they hope to defeat the ancient Enemy of All? (Summary by Gutenberg)

8Wealth of Nations, Book 4

By Adam Smith

An Inquiry into the Nature and Causes of the Wealth of Nations is the magnum opus of the Scottish economist Adam Smith, published on March 9, 1776 during the Scottish Enlightenment. It is a clearly written account of political economy at the dawn of the Industrial Revolution, and is widely considered to be the first modern work in the field of economics. (from Wikipedia)

9Triplanetary

By E. E. Smith

“Doc” E.E. Smith pretty much invented the space opera genre, and Triplanetary is a good and well-known example. Physics, time, and politics never stand in the way of a plot that gallops ahead without letup. Having earned a PhD in chemical engineering, it’s understandable that the heroes of Smith’s story are all scientists. He didn’t want to be constrained by the limits of known science, however, so in his hands the electromagnetic spectrum becomes a raw material to be molded into ever-more amazing and lethal forms, and the speed of light is no bar to traveling through the interstellar void. Come enjoy this story of yesteryear, set in tomorrow, where real women ignite love at a glance, real men achieve in days what governments manage in decades, and aliens are an ever-present threat to Life-As-We-Know-It! (Summary by Mark F. Smith)

10Spacehounds of IPC

By E. E. Smith

When the Inter-Planetary Corporation's (IPC) crack liner “IPV Arcturus” took off on a routine flight to Mars, it turned out to be the beginning of a unexpected and long voyage. There had been too many reports of errors in ship's flight positions from the Check Stations and brilliant physicist Dr. Percival (“Steve”) Stevens is aboard the Arcturus on a fact-finding mission to find out what's really happening, and hopefully save the honor of the brave pilots of the space-liner Arcturus from the desk-jockeys' in the Check Stations implications of imprecision - the nastiest insult you could cast at a ships pilot. He and the pilots are right, it was the Check Stations that were out of position, not the ships. But that's cold consolation because before the Arcturus reaches Mars it's attacked by a small, mysterious, globe shaped spaceship. (Summary from Wikipedia)

11Wealth of Nations, Book 5

By Adam Smith

An Inquiry into the Nature and Causes of the Wealth of Nations is the magnum opus of the Scottish economist Adam Smith, published on March 9, 1776 during the Scottish Enlightenment. It is a clearly written account of political economy at the dawn of the Industrial Revolution, and is widely considered to be the first modern work in the field of economics. (Introduction from Wikipedia)<br /><br />This project was proof listened by mim@can, Betty M., and Barry Eads.

This book is written to Christians who profess to believe the Bible as God's revelation, but whose "lives are filled with discomfort and unrest." Smith aims to show that the Bible's claim that God is the "the God of all comfort" is not an over-advertisement or misunderstanding, but that it is possible to avail ourselves of the doubts and heavy anxieties that plague so many Christians. <br><br> By explaining God's part and man's part, Smith aims to show her readers that it is possible to overcome feelings of defeat and despair and find rest and peace in Christ. Abundant life and genuine enduring joy are available to all believers - even you. Deep and lasting peace, beyond all Earthly circumstances, is possible. (Introduction by Rachel Craig)

LibriVox volunteers bring you 5 recordings of America by Samuel Francis Smith. This was the Weekly Poetry project for July 4th, 2010.

14Skylark of Space

By Lee Hawkins Garby and E. E. Smith

The novel begins with the accidental discovery, in a Government laboratory in Washington D. C., of a form of clean nuclear power. Our hero, Dr. Richard Seaton, uses this power to build first a flying belt and then an interstellar spaceship. He later discovers that the process operates by generation and manipulation of gravity fields.<br /><br /> When his government coworkers do not believe him, Seaton acquires rights to his discovery from the government and commercializes it with the aid of his friend, millionaire inventor Martin Crane. A former colleague, Dr. Marc DuQuesne, joins with the unscrupulous World Steel Corporation to try to steal Seaton's invention. The resulting conflict escalates, as Seaton and Duquesne develop greater and greater technical capabilities and enlist more and more powerful alien races as allies.. (Summary by Wikipedia)

15Skylark of Space (version 2)

By Lee Hawkins Garby and E. E. Smith

The Skylark of Space is one of the earliest novels of interstellar travel and is considered a classic of pulp science fiction. Originally serialized in 1928 in the magazine Amazing Stories it is often categorized as the first literary space opera, complete with protagonists perfect in mind, body, and spirit, who fight against villains of absolute evil. (Introduction from Wikipedia)

16Skylark Three

By E. E. Smith

This is a sequel to The Skylark of Space. The novel concerns Richard Seaton and his allies who have encounters with aliens while fighting DuQuesne and the Fenachrone..(Introduction by Wikipedia)

Captain John Smith (c. January 1580 – June 21, 1631) Admiral of New England was an English soldier, explorer, and author. He was knighted for his services to Sigismund Bathory, Prince of Transylvania. He is remembered for his role in establishing the first permanent English settlement in North America at Jamestown, Virginia, and his brief association with the Virginia Indian girl Pocahontas during an altercation with the Powhatan Confederacy and her father, Chief Powhatan. He was a leader of the Virginia Colony (based at Jamestown) between September 1608 and August 1609, and led an exploration along the rivers of Virginia and the Chesapeake Bay.<br /><br />His books and maps may have been as important as his deeds, as they encouraged more Englishmen and women to follow the trail he had blazed and to colonize the New World. He gave the name New England to that region, and encouraged people with the comment, "Here every man may be master and owner of his owne labour and land...If he have nothing but his hands, he may...by industrie quickly grow rich."<br /><br />In 1614, Smith returned to the Americas in a voyage to the coasts of Maine and Massachusetts Bay. He named the region "New England". He made two attempts in 1614 and 1615 to return to the same coast. First a storm dismasted his ship. In the second attempt, he was captured by French pirates off the Azores. Smith escaped after weeks of captivity and made his way back to England, where he published an account of his two voyages as A Description of New England. He never left England again. He died in the year 1631 in London at the age of 51. (Introduction by Wikipedia)

The proud, cruel and arrogant Mrs. Rayland never married. Therefore, "Rayland Hall", the old Manor House of the title, had to pass to their heir, Somerive, whom they never treated kindly. According to the British laws at the time, the heir must be the oldest son. But what is to be done when the second son is more worthy of it - and is more beloved by Miss Rayland herself? And must the fact that he is in love with a servant and dependent of Miss Rayland take its toll? (Summary by Stav Nisser)

Articles by numerous authors, compiled into a single collection for use by first year divinity students. This book is intended to be a guide to the study of the Christian religion for Protestants. It was prepared to aid students to understand various aspects of education for the Christian ministry, including basic textual studies, theology, Christian history, denominations, Christian ethics and pastoral duties. (Summary by JoeD)

20Triplanetary, First in the Lensman Series

By E. E. Smith

Triplanetary was first serialized in Amazing Stories in 1934. After the Lensman series became popular, Smith took his Triplanetary story and turned it into the first of the Lensman series, using it as a prequel to give the back story for the protaganists in the Lensmen series. He added 6 new chapters, doubling it in size and it's really a different book from the serialized novel, being published 14 years after the first. It was put into Gutenberg just last year.<br /><br /> The novel covers several episodes in an eons-long eugenics project of the super-intelligences of the Arisia. This alien race is breeding two genetic lines to become the ultimate weapon in Arisia's cosmic war with their arch enemy, the Eddore. The initial chapters cover the Kinnison genetic line during the fall of Atlantis and Nero's (Gharlane of Eddore) reign in Rome. These tales were inserted into the novel following the serialized release, along with chapters covering members of the Kinnison line in World Wars One, Two and Three. The final chapter of Triplanetary tells of the discovery of the inertialess drive that allows faster than light travel. Patrolman Conway Costigan and his friends engage in a space battle with Gray Roger the pirate gangster. This conflict is complicated by the arrival of the technologically superior, extra-Solar, amphibian-like Nevians, resulting in the first interstellar war involving humans. In this story Virgil Samms and Roderick Kinnison, two very important members of the eugenics project, are introduced. They will play the leading roles in the next story, First Lensman. (Summary by Wikipedia and Phil Chenevert)

In 1822, Aaron Smith, a young English seaman, was taken captive by Cuban pirates when his ship was boarded en route from Jamaica to England. Forced to work as a navigator and as a member of pirate boarding parties, he witnessed unspeakable acts of murder and torture. Befriended by a young Cuban woman, he managed to escape with his life, but was arrested as a pirate in Havana and sent back to England in chains. There, he found himself on trial for his life at the Old Bailey courthouse—with the attorney general himself leading the prosecution. Smith's dramatic account of his personal experience is a brutally honest, unromanticized [sic] look at piracy in the 19th century. (Summary by Google Books)

22Vortex Blaster

By E. E. Smith

Uncontrolled, terribly violent Atomic Vortices are slowly destroying civilization on every human planet throughout the galaxy. Nothing can contain or stop them despite the lensmen's best efforts until one destroys the home and family of "Storm" Cloud, brilliant atomic physicist. The tragedy triggers actions on his part that pit him one-on-one against the horrible vortices. Introducing "storm" Cloud as THE Vortex Blaster (Summary by book cover and Phil Chenevert)

23On The Seashore

By R. Cadwallader Smith

This gifted nature writer who is so good at describing animals and their habitat and habits here gives us a look at many of the fascinating creatures that can be found on the seashore. Starfish, the many types of crabs, shrimp, sea weed and finally something called the Precious Wentletrap which I will allow your imagination to think about for a while. His writing is clear and, as always, easy to read. Note that these are presented as educational 'lessons' on the various animals found near the sea and each lesson or chapter ends with a few questions called 'Exercises' which the student is asked to see if the main points of the chapter are retained. These questions have been include in the audiobook at the end of each chapter (Summary by Phil Chenevert)

Peggy Raymond and her friends, Amy, Priscilla and Ruth, encounter a new neighbour, Elaine, and her family. While Peggy, in her usual cheerful and practical manner, welcomes them into the neighbourhood of Friendly Terrace, a variety of mysteries slowly unfold about them and why they ended up moving there. (Harriet Lummis Smith later went on to write four sequels to Eleanor H. Porter's "Pollyanna" books.) (Summary by Daryl Wor)

25Within the Deep

By R. Cadwallader Smith

Presented in the form of lessons, R. Cadwallader Smith vividly portrays life in the ocean. Learn about the common and not so common that swim about in the deep, how they hunt for food and hide from enemies, visit a nursery and find out about the babies that live there, or take a stroll in an underwater garden. (Summary by Laura Victoria)

26Peggy Raymond's Vacation (or Friendly Terrace Transplanted)

By Harriet Lummis Smith

Sequel to The Girls of Friendly Terrace (or Peggy Raymond's Success). As the summer opens the girls fan themselves on the porch, wishing for a get away. As it happens, opportunity knocks, leading them into a country vacation along with a few more members to the party. (Summary by Daryl Wor)

Published in 1916, this third installment with The Friendly Terrace girls places them in The Girl’s High School, with an array of new characters, and a few peripherally known from the first book. A heavier edge of drama comes through via a new student with a superiority complex, another student whose diligent scholastic achievements mar her socially, and an odd tradition of affectionate favouritism between Freshman and Seniors which proves to be awkward and disruptive to more than just the students. Peggy, Amy, Priscilla and Ruth are again faced with new challenges, and complicated scenarios to help resolve. (Summary by Daryl Wor)

The Friendly Terrace Quartette (or Peggy Raymond At The Poplars) published in 1920, finds Peggy and her friends preparing for The Great War. Young men they had known as boys are signing up to train and fight as soldiers, while the girls find themselves looking for what they can do to help. Priscilla, and Amy join Peggy in The Land Army to assist in agricultural labour usually left to men of the period. Ruth, of weaker health, must remain on Friendly Terrace but manages to find her own way to be useful. In the station of The Land Army, known as The Poplars, Peggy, Priscilla and Amy meet many other young women who have come to lend aid, discovering their strengths and weaknesses, secrets and triumphs. (Summary by Daryl Wor)

This Christian book is written in a easy and understandable way, where the strong biblical points are clear and and applicable. The richness of the truths explained, will make one want to listen to it over and over again. The book writes about our part and God's part in the Christian life. It also reveal many secrets to the Christian life. "Today it is your happy privilege to prove, as never before, your loyal confidence in the Lord by starting out with Him on a life and walk of faith, lived moment by moment in absolute and childlike trust in Him." quote from the book. It is a must listen to Christian classic. (Summary by peppersnoodles93)