Abstract A router is used to manage network traffic and to find the best route for packets to be sent. This paper discusses the algorithms available in order to find the best route to destination for these packets in the network environment. The two main algorithms are "Global routing algorithms" and "Decentralized routing algorithms". The paper evaluates in detail these two methodologies together with their bottlenecks and illustrates examples with diagrams, graphs, tables and code.
From the Paper "In this step, routers should choose the best route for packets to every node. They do it by using an algorithm such as "Dijkstra Shortest Path Algorithm?. In this algorithm, router, based on information that has been collected from other routers, build a graph of network. This graph shows the location of routers in network and their links. Also every link will be labeled with a number that is called weight of link and is also known as cost of link. This number is a function of delay time, average traffic and sometimes simply, it is the number of hops between nodes. For example if there were two links between a node to destination, the router chooses the link with the least weight."
Abstract This research paper analyzes the growing trend of using computer science, and more specifically, genetic algorithms (expert systems) in America's businesses with special reference to the fishing industry. The author discusses the technicalities of computer systems as well as the advantages that they provide (such as saving time and money) to the American industry.
From the Paper "Who would have ever thought that the fishing industry could be greatly enhanced through the use of genetic algorithms? The fact is that more and more sectors of our business world are realizing how useful computer science is for assisting in important decisions. There is a great deal of uncertainty in the fish stock-recruitment process, just as in the auto industry. Key decisions must be made in order to gain the most profit. To help in such a situation, expert systems (ES) are used to determine the best possible solution. An ES is a ?computer system that applies reasoning methodologies to knowledge in a specific domain.? An ES is similar to a human with the biggest difference being that an ES "achieves a high level of performance in task areas that, for human beings, requires years of special education and training" (Turban 811). Without ES, fish stock assessment and management must rely on traditional analyses, which "are based on the assumption that a functional relationship exists between the size of the spawning stock and the number of fish that recruit in the future" (Chen 1)."
Tags: binary, chromosomes, computer, encoding, expert, programming, science, system, systems
Abstract This paper examines the concept of abstract authentication in federated database systems and the difficulties presented because the autonomously operated components may not know the identity of federation users. It looks at how one proposed solution is subject switching, where the federation translates the federated users identity to that of an agreed upon component subject and how this translation may be problematic due to not having component subjects with the same accesses requested by federation users. It proposes using proximity measures between requested and provided access and presents two policy neutral algorithms to find proximity minimizing matches between a federation subject and a collection of component subjects. It also explores the concepts relating to federated databases, authorization and access, and proposes some algorithms that will facilitate the subject switching method of reconciling access requirements.
Outline
Section 1
Abstract
Background
Introduction
Characteristics of Federated Databases
Homogeneous vs. Heterogeneous Databases
Agents
Agents and Meaning
Perspective
Types of Meaning
Semantics Versus Pragmatics
Context
Coverage of Communicative Acts
Mental Versus Social Agency
Section 2
Federated Database Systems and Autonomy
Design Autonomy
Communication Autonomy
Execution Autonomy
Association Autonomy
Authorization Autonomy
Distribution Transparency (i.e., Schema Integration)
Tightly Coupled
Limited Tight Coupling
Loosely Coupled
Federated Database Security
Authorization
Standards for Authentication
Decentralized vs. Centralized Authorization
Access Controls
User Based Access Control (UBAC)
Policy Based Access Control
Content Dependent Access Control (CDAC)
Context Based Access Control (CBAC)
View Based Access Control (VBAC)
Discretionary Access Control (DAC)
Mandatory Access Control (MAC)
Role Based Access Control (RBAC)
Section 3
Subject Switching
Subject Mapping Algorithms Mapping Process
Federation Mapping Process
Federation Identity
Component Mapping Process
Minimum Disparity Measure
Mapping Algorithm Create Object Sets
Identify Component Subjects
Evaluate Matching Subjects
Access Disparity Measures
Numerical Disparity Measure
Comparing Disparity Measures to Approximate Measures
Approximate Disparity Measure Comparison
Motivating Example
Access Compatibility Measures and Algorithms Compatibility of Permissions and their Disparity Measures
Cardinality
Express Specification
Section 4
Metrics
Algorithm 1 (Least Under Permitting Algorithm)
Algorithm 2 (Least Over Permitting Algorithm)
Approximations: Metrics And Mappings
Approximate Mapping Algorithms Algorithm 3 (Approximate Under Permitting Algorithm)
Algorithm 4 (Approximate Over Permitting Algorithm)
Properties of Algorithms 3 and Algorithm 4
Multilevel Federations
Non-Protected Database
Axioms
Deductive Channels Control Theorems
Signalling Channels Control Theorems
Cover Story
Multi-view Databases
Languages
Section 5
Conclusions and Ongoing Work
References
From the Paper "Heimbingner and McLeod coined the phrase Federated Database System in 1985, and Seth and Larson later confirmed the formal definition. While the term has been loosely used to refer to several different but related database systems, they more precisely and unanimously define it as a collection of cooperating but autonomous component database systems. [SL90] (According to Oszu 1999, semi-autonomous systems are termed federative DBMS). A federated database system represents a compromise between no integration, wherein users must explicitly interface with multiple autonomous databases, and total integration, where the autonomy of each distinct database is sacrificed in order to allow users access through a single global interface."
Abstract This paper attempts to investigate different types of solutions to the obstacle of synchronizing multiple processes in a multiprocessor system while retaining shared data integrity between concurrent processes working on that shared data. It discusses how the works presented in the paper are relevant and significant because there is a growing need for faster and more efficient algorithms that deal with inter-process communication and mutual exclusion.
Outline:
Abstract
Introduction
Blocking Algorithms Blocking Algorithm Problems
A Non-Blocking Algorithm The Future of Mutual Exclusion
Conclusion
From the Paper "Fundamentally, shared data access management plays a crucial role in parallel processing within multiprocessor computing systems. "The problem of mutual exclusion is that of guaranteeing that certain sections of code will not be executed by more than one process simultaneously" [Kesteloot, 1995]. "Mutual exclusion algorithms are used to resolve conflicting accesses to shared resources by asynchronous, concurrent processes" [Anderson, 2001]. In single processor (uniprocessor) systems, mutual exclusion is reasonably implemented by temporarily disabling interrupts to ensure that access and potential modification to the shared data is only achieved by exactly one thread of execution at a time without disruption. "
Abstract This paper gives some algorithms for thinning a monochrome image and checks out the development in other algorithms. It explains that thinning is an important preprocessing step for many image analysis operations such as optical character recognition, fingerprint recognition and document processing. This paper studies the results of some of the various popularly implemented thinning algorithms like medial axis method [2], contour generation method [3], local thickness based thinning approach [4], hybrid Approach and sequential and parallel thinning [5], and to debate on the advantages and disadvantages of the different methods along with citing the places where each of them is optimally utilized.
From the Paper "Communication is an integral component of human society that has been greatly enhanced by the evolution of the technological age. Verbal communication has been greatly revolutionized by the advent of television, telephone and radio, and written communication has been transformed by development of word processors and electronic data. It is hence becoming increasing important to have information available for examination and manipulation in the digital format, and Optical Character Recognition (OCR) methods have been created towards this end. Character Recognition or Optical Character Optical Character Recognition (OCR) is the process of converting scanned images of machine printed or handwritten text (numerals, letters, and symbols), into a computer process able format (such as ASCII). The recognition of optically processed symbols and numerals, that is their translation from human readable forms to machine codes, holds excessive practical applicability in data transmission and documentation as well as for specific applications like identification of postal(zip) codes."
Abstract This paper discusses an intrusion detection algorithm for analyzing university web server log files. It also discusses integrating hierarchical clustering with other algorithms for an intrusion detection system. The paper proposes to use hierarchical clustering as the main back bone of the intrusion detection system and then incorporating other algorithms like statistics and support vector machines (SVM) as needed.
From the Paper "The initial plan was to use the user signatures method by Seth Freeman or the Traffic Classification technique but the first method seems more suited to an OS than for web server log files and the second seems a lot more complicated and also requires a destination IP, which is not readily available from our log files. I started out by writing a statistics based algorithm but then added hierarchical clustering based on instructor feedback. Eventually I settled on this paper based on hierarchical clustering with other methods as backup although I still like the statistics approach."
Definitions, algorithms and optimizations used to achieve automatic memory management in computer programming languages without programmer involvement.
Abstract The value of garbage collection (GC) to the discipline of software engineering is established. The definitions of the fundamental GC terms are given. Thereafter, the three major GC algorithms are discussed and graphically represented. Basic differences and similarities among the algorithms are considered. The two major GC optimization techniques and their historical origins are discussed. The paper includes diagrams.
From the Paper "Garbage collection (GC) is the automatic management of dynamic memory allocation. The alternative to this is programmer-controlled dynamic memory allocation. Automatic management is the superior of the two because programmer-controlled management can lead to memory leaks, bugs caused by accidental manipulation of program code and data through pointers, and an overall increase in program complexity. These in turn consume a considerable amount of programmer time and result in higher software maintenance costs. Automatic management prevents these issues and allows programmers to focus on the programming that relates directly to useful system functionality."
Abstract This piece is a introduction to the network security technology known as IPSec. IPSec is an open standard for IP security and uses several protocols and algorithms to provide a customizable, robust security system for system administrators. The various applications, protocols and algorithms are discussed, followed by a brief discussion of how the technology works. Then, the advantages of IPSec, including e-commerce and mobile computing, are discussed briefly. A table of contents is included to make navigating the headings and subheadings easier.
Abstract Discusses differences between a code and a cipher. Requirements of each; how each works. History of encryption. Enigma machine of World War II. Pre-computer encrption. Development of computer program to encrypt data. Function of a "hash" (a number generated from text & smaller than the text itself). Privacy issues. Future of algorithms.
From the Paper "Encryption and Hash Algorithms
Introduction
Stephen Levy (2001), reporting on the latest "unbreakable code" begins his report by quoting Edgar Allan Poe. "It may roundly be asserted that human ingenuity cannot concoct a cipher which human ingenuity cannot resolve" (Levy, 2001, 45). This article was selected to lead off this discussion of encryption because of two elements of confusion.
First, the headline read "An Unbreakable Code"? and the article was about enciphering and deciphering, also called "encryption" and ?decryption.? This is a common, and often-repeated mistake, one which can confuse the very field of study. A "code" is not a "cipher" anymore than a "tennis ball" is a ?cabbage.?
Abstract This paper explains the hypotheses of this project, which are: (1) Little can be done to impact a solution's floppy disk speed, (2) SCSI disks no longer affect performance, and (3) much can be done to affect a system's 10th-percentile instruction rate. The author reports, running "Sackbut" on commodity operating systems, such as LeOS and Minix, the experiments proved that exo-kernelizing the saturated online algorithms was more effective than monitoring them. This paper concludes that the author's system sets a precedent for the visualization of robots, and it is expected that cryptographers will improve on Sackbut for years to come. Tables.
Table of Contents
Introduction
Reliable Communication
Implementation
Results and Analysis
Hardware and Software Configuration
Experimental Results
Related Work
Conclusion
From the Paper "Contrarily, this solution is fraught with difficulty, largely due to digital-to-analog converters. Predictably, Sackbut constructs fiber-optic cables. Existing constant-time and classical heuristics use extensible technology to develop the intuitive unification of the partition table and the Turing machine. We view steganography as following a cycle of four phases: synthesis, construction, storage, and emulation. Such a hypothesis is entirely an unfortunate mission but has ample historical precedence. The basic tenet of this solution is the important unification of linked lists and A* search. Combined with the Ethernet, such a claim constructs an analysis of the transistor."
Abstract This paper discusses the secure shell (SSH) protocol. It provides a brief overview of the secure shell protocol including its origin and why it was developed and the current state of the secure shell protocol. It then focuses on the secure shell protocol itself which consists of the transport, user authentication, connection protocols and the secure shell packet configuration. A discussion of the client and server costs of secure shell including the availability of the open version of secure shell (OpenSSH) follows, with a comparison of the differences between the commercial and free versions available for downloading. It ends with a discussion of the usage of secure shell and a working practical example of how secure shell clients and servers interact with one another.
Outline
Introduction
Secure Shell Overview
Secure Shell Protocol
Transport Layer
User Authentication Layer
Connection Layer
Encryption
Public Key Algorithms Components of Secure Shell
Secure Shell Costs
Secure Shell Usage
SSH Tunneling Example
Conclusion
Bibliography
From the Paper "The traditional insecure methods of connecting to networks using telnet, remote shell (RSH), or file transfer protocol (FTP), transfer commands and passwords in clear text, making them vulnerable to security attacks. These insecure protocols may now be replaced by using the SSH protocol which encrypts the clear text into an unreadable format which eliminates the risk of the message being read if captured in transmission."
Abstract This study examines the use of advanced techniques of data clustering in algorithms that employ abstract categories for the pattern matching and pattern recognition procedures used in data mining searches of web documents. The paper discusses the significance and purpose of the study. The author gives exact methodology, organization and statistical results of the study. It also evaluates implementation of data clustering for web based searches and its feasibility.
Table of Contents
Background of the Problem
Significance of the Study
Definitions
Overview of the Methodology
Organization of the Study
Purpose of the Study
Background and a Review of Literature
Alternative Solutions
Feasibility Tests
Evaluation and Implementation
References
From the Paper "Documents are commonly represented as vector space models. In this model, each document is represented by a point in the space that roughly corresponds with the union of the primary words in the document. The process includes filtering out common words (such as pronouns and conjunctions), ignoring words that are unique to the document, and words are stemmed in order to reduce them to canonical form. Once this is done , the document can be expressed in the form of vectors, and then those vectors can be used to plot a pint in virtual space that represents that specific document. The words of the document are also weighted; without this provision, the more commonly a word appears in a document, the more important it is considered (which is often not really the case). Conversely, words that appear infrequently in a document are considered discriminatory- they serve as a distinguishing feature for the document in question.[10]"
Abstract The author of the paper describes Andrew J. Viterbi as a great engineer of the past and present century and states that his success in communication systems helped the United States become a world leader in technological competition. In particular, the writes cites the famous Viterbi algorithm and achievements in CDMA cell phone development. The paper chronicles Viterbi's life from when he left Italy with his parents in the summer of 1939, the family's struggle to settle in the US and Viterbi's development into one of the country's leading engineers. The paper is accompanied by a number of photographs.
Outline:
A Genius of the Past and Present: Andrew J. Viterbi
Linkabit and Qualcomm. His creations.
Works Cited
From the Paper "At a very young age Viterbi was already dreaming of becoming an engineer. When his family moved to Boston, he used to spend his time day dreaming about attending the Massachusetts Institute of Technology (MIT). MIT is one of the highest ranked universities not only in the US, but worldwide. Viterbi would visualize himself as a student at MIT, but he knew his family could not afford it at that time and he would have to work hard in order to have a chance to get there, Viterbi had to get a scholarship (Morton). With hard work and a strong will Viterbi got it. He was ranked fourth among 225 students in his class and was accepted by MIT. He still had to work part time in order to fulfill his needs. He worked at Raytheon in the semiconductor area. At that time it was called the "transistor department." As he studied, he was already working as an engineer on communication equipment, designing electrical circuits and writing some diagnostic programs for radio links and early television. In the evenings he had classes."
Tags:algorithm communication radio satellite education Qualcomm Linkabit space, jet propulsion laboratory, MIT
Abstract This paper explains that Claude Levy-Strauss in his book "The Structural Study of Myth" breaks down myths structurally into four themes. The paper then describes the way that Strauss uses his algorithm to interpret any story through a prescribed matrix. The writer relates that she took a few stories and applied Claude Levy-Strauss' technique to them with excellent results; however, she does question the value of his specific four themes and in analyzing myths in this structural fashion.
From the Paper "What Strauss is doing is similar in practice to what a number of the other writers that we have already covered have tried to do. It is another type of analysis in which we're taking something that's essentially abstract (myth) and trying to apply concrete algorithms to it. With that in mind, I immediately have some level of skepticism. Putting that aside for a moment though, I do see quite a bit of validity in Levy-Strauss is technique in that it does successfully manage to take abstract concepts and organize them structurally."
Abstract The paper explains the concept of securities trading that can work with a combination of high-speed computer processing with complex mathematical algorithms. The paper outlines the evolution of automation and discusses the benefits and risks associated with automated trading processes. The paper considers the implications for the future and concludes that ultimately, these systems have the potential to further revolutionize the financial investment industries far beyond their present-day capabilities.
Outline:
The Mathematical Basis of Securities Trading
The Evolution of Automation
Benefits Associated with Automated Trading Processes
Risks Associated with Automated Trading Processes
Implications for the Future
From the Paper "In principle, the concept of securities trading is readily reducible to mathematical relationships capable of predicting future stock performance on the basis of previous trends in the market (Skypala, 2006). However, myriad factors that do not immediately appear relevant to the stock market also have great potential to influence the market. This has always been true, (as illustrated very simply by the relationship between wars or other serious global occurrences during peacetime throughout the 20th century), but since the computer age and the 24-hour news cycle, events external to the market play a much larger role than before (Duhigg, 2006)."
