Thesis (M.S. in Computer Science)--Naval Postgraduate School, June 1990. / Thesis Advisor(s): Shimeall, Timothy J. Second Reader: Bradbury, Leigh W. "June 1990." Description based on signature page on October 16, 2009. DTIC Descriptor(s): Computer programs, costs, faults, measurement, test methods DTIC Indicator(s): Computer program verification, metric system, Theses. Author(s) subject terms: Software metrics, text-based metrics, faults, testing, empirical studies. Includes bibliographical references (p. 69-72). Also available online.

Thesis (Ph. D.)--Oregon State University, 1987. / Typescript (photocopy). Includes bibliographical references (leaves 97-101). Also available on the World Wide Web.

As people go about their lives, they form a variety of social relationships, such as family, friends, colleagues, and acquaintances, and these relationships differ in their strength, indicating the level of trust among these people. The trend in these relationships is for people to trust those who they have met in real life more than unfamiliar people whom they have only met online. In online social network sites the objective is to make it possible for users to post information and share albums, diaries, videos, and experiences with a list of contacts who are real-world friends and/or like-minded online friends. However, with the growth of online social services, the need for identifying trustworthy people has become a primary focus in order to protect users’ vast amounts of information from being misused by unreliable users. In this thesis, we introduce the Capacity- first algorithm for identifying a local group of trusted people within a network. In order to achieve the outlined goals, the algorithm adapts the Advogato trust metric by incorporating weighted social relationships. The Capacity-first algorithm determines all possible reliable users within the network of a targeted user and prevents malicious users from accessing their personal network. In order to evaluate our algorithm, we conduct experiments to measure its performance against other well-known baseline algorithms. The experimental results show that our algorithm’s performance is better than existing alternatives in finding all possible trustworthy users and blocking unreliable ones from violating users’ privacy.

This thesis covers fundamental properties of metric spaces, as well as completeness, compactness, and separability of metric spaces.

Although it was invented by Mikhail Gromov, in 1987, to describe some family of groups[1], the notion of Gromov hyperbolicity has many applications and interpretations in different fields. It has applications in Biology, Networking, Graph Theory, and many other areas of research. The Gromov hyperbolicity constant of several families of graphs and geometric spaces has been determined. However, so far, the only known algorithm for calculating the Gromov hyperbolicity constant δ of a discrete metric space is the brute force algorithm with running time O (n4) using the four-point condition. In this thesis, we first introduce an approximation algorithm which calculates a O (log n)-approximation of the hyperbolicity constant δ, based on a layering approach, in time O(n2), where n is the number of points in the metric space. We also calculate the fixed base point hyperbolicity constant δr for a fixed point r using a (max, min)−matrix multiplication algorithm by Duan in time O(n2.688)[2]. We use this result to present a 2-approximation algorithm for calculating the hyper-bolicity constant in time O(n2.688). We also provide an exact algorithm to compute the hyperbolicity constant δ in time O(n3.688) for a discrete metric space. We then present some partial results we obtained for designing some approximation algorithms to compute the hyperbolicity constant δ.

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<p> A class of Banach algebras which generalize the idea of the Lipschitz algebra on a metric space is studied. It is shown that homomorphisms of these algebras correspond to mappings of the underlying space which satisfy certain moduli of continuity. The relation is expressed in categorical terms, and application is made to the theory of quasiconformal mapping. </p> / Thesis / Doctor of Philosophy (PhD)

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In this thesis, we present a new register-transfer level (RTL) test generation method that makes use of two coverage metrics, Branch Coverage, and Mutation Coverage across two stages, to cover hard-to-reach points previously unreached. We start with a preprocessing stage by converting the RTL source to a C++ equivalent using a modified Verilator, which also automatically creates mutants and the corresponding mutated C++ design, based on arithmetic, logical and relational operators during conversion. With the help of extracted Data Dependency and Control Flow Graphs, in every <golden, mutation> pair, branches containing variables dependent on the mutated statement are instrumented to track them. The first stage uses Evolutionary algorithms with Ant Colony Optimization to generate test vectors with mutation coverage as the metric. Two new filtering techniques are also proposed which optimize the first stage by eliminating the need for generating tests for redundant mutants. The next stage is the original BEACON which now takes the generated mutation test vectors as the initial population unlike random vectors, and output final test vectors. These test vectors succeed in improving the coverage up to 70%, compared to the previous approaches for most of the ITC99 benchmarks. With the application of filtering techniques, we also observed a speedup by 85% in the test generation runtime and also up to 78% reduction in test vector size when compared with those generated by the previous techniques. / MS / In the recent years, Verification has become one of the major bottlenecks in integrated circuit design process, which is exacerbated by the increasing design complexities today. Today designers start the design process by abstracting the initial design in a manner similar to software programming language using a higher abstraction language called Hardware Descriptive Language(HDL). Hence, an HDL based design also contains a number of case statements and if-else statements, also called branches, similar to a software design. Branches indicate decision points in the design and high branch coverage based tests can give us an assurance that the design is properly exercised as compared to those given by randomly generated tests. In this thesis, we introduce a new test generation methodology which generates tests using the help of user introduced mutants to ensure higher branch coverage. Mutation testing is similar to a fault testing method, in which an error or a fault is deliberately introduced into the design and we check if the tests generated are able to detect the fault. An important property of a mutant is that: when a mutant is applied and if the mutated part of the design is exercised by the given test suite, then the following data and control flow path taken can be different from that taken on the original design. This important property along with proper guidance is used in our work to reach some branches which are difficult to cover by random test vectors, and this is the main basis of this thesis. Applying this method, we observed that the branch coverage increased with a decrease in test generation runtime and test vector length when compared to previously proposed techniques.