Formal verification is required for systems that require high assurance. Formal verification can require large and complex proofs that can drastically affect the development life cycle. Through the use of a verification system, such proofs can be managed and completed in an efficient manner. A verification system consists of a specification language that can express formal logic, and an automated theorem tool that can be used to verify theorems and conjectures within the specifications. One example of a verification system is Specware. This thesis presents an analysis of Specware against a set of evaluation criteria in order to determine the level of usefulness Specware can have in the verification of high assurance systems. This analysis revealed that Specware contains a powerful specification language capable of representing higher order logic in a simple and expressive manner. Specware is able to represent multiple levels of abstraction and generate proof obligations regarding specification correctness and interlevel mapping. The theorem prover associated with Specware was found to be lacking in capability. Through this analysis we found that Specware has great potential to be an excellent verification system given improvement upon the theorem prover and strengthening of weaknesses regarding linguistic components. / Naval Postgraduate School author (civilian).

Information asymmetry literature has developed models that explain the relation between uninformed traders and informed traders. In general, these models have shown that first, information asymmetry is a driving force for investor buying and selling behavior. Second, the trades of informed investors reveal some of the information they possess suggesting that the trades of informed investors are informative to market makers. Third, when information about a stock enters the market, the characteristics of the firm can change, e.g., a better information environment reduces the cost of capital (Admati, 1985; Easley and O‟Hara, 2004; Wang, 1993). In this study, I apply information asymmetry theory to explore the trading behavior of active equity mutual fund managers and their role as facilitators of information. In the first essay, I study the information environment of firms mutual funds choose to add to their holdings and how it changes after the inclusion. I identify all new additions to the mutual fund holdings universe from 2002 to 2015 and compare them to the available universe of firms not yet owned by mutual funds. I find that active equity mutual fund managers behave as informed investors and prefer to buy stocks with more opaque information environments i.e., firms with larger spreads, lower trading volume, smaller firms with more growth opportunities, and firms that tend to use more accruals. Fund managers also show a preference for firms that have less analyst following, those in which analysts are less likely to agree on their EPS estimates, and firms in which analysts are more likely to err in their predictions. In other words, mutual fund managers prefer firms that are more likely to be mispriced. Once the funds include the firms, I document a strong improvement in their information environment. Firms attract more analyst coverage, reduce its use of accruals, produce more guidance, increase their market cap, and show increased turnover. The second essay focuses on the herding behavior of mutual funds. The study is the first to document the herding of mutual fund managers after creation of toehold positions by portfolio managers. I use a hand-collected dataset consisting of all toehold acquisitions reported to the SEC from 1995 to 2015 to document a strong herding reaction of active equity mutual funds after toehold announcements. This herding reaction is several times stronger than other mutual fund herding events reported by previous literature. I also document that the strength of the herding reaction varies depending on the identity of the filer or the characteristics of the firm acquired. The herding reaction is stronger for toehold announcements of firms with a smaller market capitalization, better growth opportunities, and those that are more illiquid. I also find that the herding reaction is weaker after the filings of hedge fund managers. My results support the informational herding cascade hypothesis. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

Bilayer magnetic nanostructures are currently of interest in a variety of applications due to the ability to combine complementary properties of each layer. One key area is data storage where extending hard disk drive (HDD) storage density may be achieved by storing each bit of data in an individual magnetic nanostructure. Whilst several magnetometry techniques are capable of measuring the properties of arrays of magnetic nanostructures, very few are sensitive enough to measure an individual magnetic nanostructure. An electrical technique termed anomalous Hall effect (AHE) magnetometry is used in this work due to its high sensitivity. In this technique the structure is fabricated on a Hall cross, and a current is applied and the transverse voltage measured whilst sweeping an external magnetic field. Bilayer magnetic nanostructures formed from separated Co/Pd and Co/Ni multilayers were measured for the first time with this technique, which showed that an asymmetry is seen in their hysteresis loops when the two layers are magnetically decoupled. It is demonstrated that this is due to a combination of a very small giant magnetoresistance (GMR) effect present in the magnetic nanostructure, and the Hall cross offset voltage which results from small imperfections in the shape of the cross. A finite element simulation is used to provide quantitative evidence for this model. These results indicate that asymmetry will be seen in Hall measurements of other materials which exhibit magnetoresistance. Bilayers of FePt and FeRh were also investigated as these materials are of interest for a future HDD system where the structure is heated, and the FeRh undergoes a ferromagnetic transition causing it to assist the switching of the FePt. These thin films are difficult to deposit whilst achieving chemical ordering in both layers. FeRh/FePt films are deposited, before greater ordering is demonstrated with an FePt/FeRh film. It is demonstrated that AHE magnetometry can provide a similar level of measurement information of bilayer nanostructures of these materials as bulk magnetometry techniques can provide of the thin film.

One unresolved question in hadronic physics is the origin of large transverse single-spin asymmetries, AN, observed in hadron production from high-energy polarized-proton collisions. Collinear perturbative Quantum Chromodynamics (pQCD) predicts that AN should scale with the quark mass, however, experiments have since reported large AN for inclusive hadron production. Recent measurements from RHIC experiments show examples of these asymmetries at forward angles in a kinematic region where pQCD cross-section calculations reasonably agree with measured cross-sections. Disentangling dynamical contributions to AN from hadro-production requires moving beyond inclusive measurements. One possibility is to investigate asymmetries in two-particle correlations due to Interference Fragmentation Functions (IFF) and the Sivers effect. In 2008, RHIC dedicated a portion of the run to transversely polarized proton collisions at sqrt(s) = 200 GeV. STAR was equipped with a Foward Meson Spectrometer (FMS) and a Forward Time Projection Chamber (FTPC), overlapping in the pseudorapidity range of 2.5 < eta &lt; 4. By analyzing neutral pions with the FMS correlated with charged particles from the FTPC, correlation asymmetries can be measured at kinematics where large inclusive asymmetries have been measured. Correlations are measured for pi^0's with 2 &lt; pT, pi^0 &lt; 5 GeV/c and associated charged particles in two ranges of transverse momentum: 1 &lt; pT, ch &lt; 2 GeV/c and 0.5 &lt; pT, ch &lt; 1 GeV/c. IFF and Sivers asymmetries manifest themselves through the correlation of two particles from the same jet. These events are selected through a cut on the pair radius, delta R. Gain non-uniformities and electronics failures have resulted in large holes in trigger acceptance and associated particle acceptance, respectively. This non-uniform acceptance allows the Sivers and IFF effects to mix and distort the raw asymmetries. Techniques are developed to measure this leak-through by means of unpolarized yields and event weighting. They result in small corrections to the asymmetries. IFF and Sivers asymmetries both for xF > 0 and for xF &lt; 0 are reported for forward-angle pi^0-charged particle correlations from polarized-proton collisions at sqrt(s) = 200 GeV. Asymmetries are shown corrected for full underlying-event and pileup backgrounds, as well as corrected only for pile-up contributions. It appears the asymmetries are less sensitive to delta R when corrected for the full underlying-event background. Unfortunately, statistics limitations preclude a firm conclusion.

In this dissertation, we investigate three different questions that are related to information asymmetry and principal-agent problems. The first question is whether principal-agent conflicts lead executives to influence the design of their own employment contracts to exploit the shareholders; the second is the question whether conflicts of interest hamper the effectiveness of affiliated analysts in detecting and curbing earnings management; and the third is whether small investors are at an informational disadvantage. The three studies provide evidence on the existence of information asymmetry and principal-agent problems in various contexts. In particular, we find that the benchmarking process of executive compensation observed is a remedy of the agency costs incurred; that analysts from independent research firms monitor firms they cover more effectively than analysts affiliated with investment banks; and, strikingly, that small investors actually may have better information regarding firms’ financials even when compared to professional equity analysts. Together, these studies provide new insights into the cornerstone problems of the finance literature. / Thesis (Ph.D, Management) -- Queen's University, 2010-04-29 14:19:56.636