Formal verification techniques have been widely deployed as means to ensure the quality of software products. Unfortunately, they suffer with the combinatorial explosion of the state space. That is, programs have a large number of states, sometimes infinite. A common approach to alleviate the problem is to perform the verification over abstract models from the program. Control-flow graphs (CFG) are one of the most common models, and have been widely studied in the past decades. Unfortunately, previous works over modern programming languages, such as Java, have either neglected features that influence the control-flow, or do not provide a correctness argument about the CFG construction. This is an unbearable issue for formal verification, where soundness of CFGs is a mandatory condition for the verification of safety-critical properties. Moreover, one may want to extract CFGs from the available components of an open system. I.e., a system whose at least one of the components is missing. Soundness is even harder to achieve in this scenario, because of the unknown inter-dependences between software components. In the current work we present a framework to extract control-flow graphs from open Java Bytecode systems in a modular fashion. Our strategy requires the user to provide interfaces for the missing components. First, we present a formal definition of open Java bytecode systems. Next, we generalize a previous algorithm that performs the extraction of CFGs for closed programs to a modular set-up. The algorithm uses the user-provided interfaces to resolve inter-dependences involving missing components. Eventually the missing components will arrive, and the open system will become closed, and can execute. However, the arrival of a component may affect the soundness of CFGs which have been extracted previously. Thus, we define a refinement relation, which is a set of constraints upon the arrival of components, and prove that the relation guarantees the soundness of CFGs extracted with the modular algorithm. Therefore, the control-flow safety properties verified over the original CFGs still hold in the refined model. We implemented the modular extraction framework in the ConFlEx tool. Also, we have implemented the reusage from previous extractions, to enable the incremental extraction of a newly arrived component. Our technique performs substantial over-approximations to achieve soundness. Despite this, our test cases show that ConFlEx is efficient. Also, the extraction of the CFGs gets considerable speed-up by reusing results from previous analyses. / <p>QC 20121029</p> / Verification of Control-Flow Properties of Programs with Procedures(CVPP)

The aim of this study was to compare online child pornography offenders and contact offenders along the predictive items of the Static-2002 actuarial risk assessment tool, as well as, several other items and scales predictive of recidivism. In addition, the study wished to determine if the Static-2002 was a well-equipped to assess online offenders. 120 subjects were assessed in this study, 53 online child pornography offenders, 53 child molesters, and 7 offenders who committed both a contact and online offense. The research identified a number of similarities between the two groups of offenders, including a finding that the two groups did not significantly differ in age. The most pronounced differences were found on the several measures of criminality used in the study where contact offenders scored significantly higher. The Static-2002 was found to not be well suited for use with online offenders as the tool had difficulty assessing their sexual deviancy.

Concurrent software is quickly becoming a very important facet in Software Engineering due to numerous advantages, one of which is increased processing speed. Despite it's importance, concurrent software is fraught with very difficult to detect bugs, for example deadlocks and data races. Concurrency design patterns were created to o er successfully tried and tested means to design and develop concurrent software to, amongst other things, minimize the occurrence of these hard to detect bugs. In this thesis we discuss our novel static analysis technique to detect these concurrency design patterns in Java source code and identify them using commented Java annotations. Using our technique the commented Java annotations are inserted above Java constructs that are not only part of the Java source code but also make up the various roles that comprise the concurrency design pattern. The identifying of the concurrency design patterns in the Java source code can aid in their maintenance later on, by matching the inserted Java annotations to the various Java constructs they are annotating. Maintaining the concurrency design patterns within the Java source code in effect aids in maintaining the Java source code error free. / UOIT

The purpose of this thesis is to give a preliminary investigation into the effect of wing deformation on flight dynamics. The candidate vehicle is FW-11 which is a flying wing configuration aircraft with high altitude and long endurance characteristics. The aeroelastic effect may be significant for this type of configuration. Two cases, the effect of flexible wing on lift distribution and on roll effectiveness during the cruise condition with different inertial parameters are investigated. For the first case, as the wing bending and twisting depend on the interaction between the wing structural deflections and the aerodynamic loads, the equilibrium condition should be calculated. In order to get that condition, mass, structure characteristics and aerodynamic characteristics are estimated first. Then load model and aerodynamic model are built. Next the interaction calculation program is applied and the equilibrium condition of the aircraft is calculated. After that, effect of wing flexibility on lift parameters is investigated. The influence of CG, location of lift and location of flexural axis are investigated. The other case is to calculate the transient roll rate response and estimate the rolling effectiveness of flexible aircraft, and compared with the rigid aircraft’s. A pure roll model is built and derivatives both for the rigid wing and the flexible wing are estimated. It has been found that flexible wing leads to the loss of control effectiveness, even cause reversal when reduces the structure natural frequency. The influence of inertia data for flexible roll is also investigated.

The aim of this study was to compare online child pornography offenders and contact offenders along the predictive items of the Static-2002 actuarial risk assessment tool, as well as, several other items and scales predictive of recidivism. In addition, the study wished to determine if the Static-2002 was a well-equipped to assess online offenders. 120 subjects were assessed in this study, 53 online child pornography offenders, 53 child molesters, and 7 offenders who committed both a contact and online offense. The research identified a number of similarities between the two groups of offenders, including a finding that the two groups did not significantly differ in age. The most pronounced differences were found on the several measures of criminality used in the study where contact offenders scored significantly higher. The Static-2002 was found to not be well suited for use with online offenders as the tool had difficulty assessing their sexual deviancy.

Hydrogenated nitrile butadiene rubber (HNBR) which is known for its excellent elastomeric properties and mechanical retention properties after long time exposure to heat, oil and air is produced by the catalytic hydrogenation of nitrile butadiene rubber (NBR). Hydrogenation of NBR is carried out preferably in solution via homogeneous catalysis. As yet, it is being commercially produced in a semi-batch process where gaseous hydrogen continuously flows into a batch of reactant polymer. Several catalysts have been exploited successfully for the hydrogenation of NBR in organic solvents, which include palladium, rhodium, ruthenium, iridium and osmium complexes. Owing to the drawbacks of batch production (such as time taken for charging and discharging the reactants/products, heating and cooling, reactor clean up), and the huge demand for HNBR, a continuous process is proposed where potential time saving is possible in addition to the high turn over of the product. Numerical investigation of the HNBR production in a plug flow reactor and a continuous stirred tank reactor showed that a reactor with plug flow behavior would be economical and efficient. A static mixer (SM) reactor with open-curve blade internal geometry is designed based on the simulation and hydrodynamic results. The SM reactor was designed with 24 mixing elements, 3.81 cm ID and 90 cm length. The reactor has a jacket in which steam is used to heat the polymer solution. The hydrodynamics in the SM reactor (open-flat blade structure) with air-water system showed that plug flow could be achieved even under laminar flow conditions (Reh < 20). For a constant mean residence time, the Peclet number was varying such that it is 4.7 times the number of mixing elements (ne) used in the SM reactor. Empirical correlations were developed for gas hold up (εG) and overall mass transfer coefficient (KLa). The mass transfer experiments showed that high KLa, 4 to 6 times compared to that of the conventional reactors could be achieved in the SM reactor at particular operating conditions. Very important information on the Peclet number, liquid hold were obtained from the hydrodynamic experiments conducted with the actual working fluids (hydrogen, polymer solutions) in the SM reactor. The superficial gas velocity had an adverse effect on both Peclet number and liquid hold up. The viscosity of the polymer solution also had a marginal negative effect on the Peclet number while a positive effect on the liquid hold up. The hydrogenation performance with the homogeneous catalyst OsHCl(CO)(O2)(PCy3)2 was performed in the continuous process with SM reactor. Complete hydrogenation of NBR was possible in a single pass. The effect of mean residence time, catalyst and polymer concentration on the final degree of hydrogenation was studied. The minimum catalyst required to achieve degree of hydrogenation over 97% was empirically found and an empirical correlation was developed for degree of hydrogenation as a function of operating conditions and parameters. Hydrogenation in the SM reactor is modeled by using plug flow with axial dispersion model that is coupled with the concentrations of carbon-carbon double bond, hydrogen and osmium catalyst. The model involves coupled, non-linear partial differential equations with different dimensionless parameters. The proposed model was verified with the experimental results obtained from the hydrogenation and hydrodynamic experiments. The model could satisfactorily predict the degree of hydrogenation obtained from experimental results at various operating conditions. In general, the designed continuous process with SM reactor performed well and was an effective method of manufacturing HNBR on a continuous basis. The designed system is amicable to the industrial operating conditions and promises to be highly efficient and economic process for production of HNBR.

Hydrogenated nitrile butadiene rubber (HNBR) which is known for its excellent elastomeric properties and mechanical retention properties after long time exposure to heat, oil and air is produced by the catalytic hydrogenation of nitrile butadiene rubber (NBR). Hydrogenation of NBR is carried out preferably in solution via homogeneous catalysis. As yet, it is being commercially produced in a semi-batch process where gaseous hydrogen continuously flows into a batch of reactant polymer. Several catalysts have been exploited successfully for the hydrogenation of NBR in organic solvents, which include palladium, rhodium, ruthenium, iridium and osmium complexes. Owing to the drawbacks of batch production (such as time taken for charging and discharging the reactants/products, heating and cooling, reactor clean up), and the huge demand for HNBR, a continuous process is proposed where potential time saving is possible in addition to the high turn over of the product. Numerical investigation of the HNBR production in a plug flow reactor and a continuous stirred tank reactor showed that a reactor with plug flow behavior would be economical and efficient. A static mixer (SM) reactor with open-curve blade internal geometry is designed based on the simulation and hydrodynamic results. The SM reactor was designed with 24 mixing elements, 3.81 cm ID and 90 cm length. The reactor has a jacket in which steam is used to heat the polymer solution. The hydrodynamics in the SM reactor (open-flat blade structure) with air-water system showed that plug flow could be achieved even under laminar flow conditions (Reh < 20). For a constant mean residence time, the Peclet number was varying such that it is 4.7 times the number of mixing elements (ne) used in the SM reactor. Empirical correlations were developed for gas hold up (εG) and overall mass transfer coefficient (KLa). The mass transfer experiments showed that high KLa, 4 to 6 times compared to that of the conventional reactors could be achieved in the SM reactor at particular operating conditions. Very important information on the Peclet number, liquid hold were obtained from the hydrodynamic experiments conducted with the actual working fluids (hydrogen, polymer solutions) in the SM reactor. The superficial gas velocity had an adverse effect on both Peclet number and liquid hold up. The viscosity of the polymer solution also had a marginal negative effect on the Peclet number while a positive effect on the liquid hold up. The hydrogenation performance with the homogeneous catalyst OsHCl(CO)(O2)(PCy3)2 was performed in the continuous process with SM reactor. Complete hydrogenation of NBR was possible in a single pass. The effect of mean residence time, catalyst and polymer concentration on the final degree of hydrogenation was studied. The minimum catalyst required to achieve degree of hydrogenation over 97% was empirically found and an empirical correlation was developed for degree of hydrogenation as a function of operating conditions and parameters. Hydrogenation in the SM reactor is modeled by using plug flow with axial dispersion model that is coupled with the concentrations of carbon-carbon double bond, hydrogen and osmium catalyst. The model involves coupled, non-linear partial differential equations with different dimensionless parameters. The proposed model was verified with the experimental results obtained from the hydrogenation and hydrodynamic experiments. The model could satisfactorily predict the degree of hydrogenation obtained from experimental results at various operating conditions. In general, the designed continuous process with SM reactor performed well and was an effective method of manufacturing HNBR on a continuous basis. The designed system is amicable to the industrial operating conditions and promises to be highly efficient and economic process for production of HNBR.

The Guaranteed Minimum Withdrawal Benefits (GMWBs) are optional riders provided by insurance companies in variable annuities. They guarantee the policyholders' ability to get the initial investment back by making periodic withdrawals regardless of the impact of poor market performance. With GMWBs attached, variable annuities become more attractive. This type of guarantee can be challenging to price and hedge. We employ two approaches to price GMWBs. Under the constant static withdrawal assumption, the first approach is to decompose the GMWB and the variable annuity into an arithmetic average strike Asian call option and an annuity certain. The second approach is to treat the GMWB alone as a put option whose maturity and payoff are random. Hedging helps insurers specify and manage the risks of writing GMWBs, as well as find their fair prices. We propose semi-static hedging strategies that offer several advantages over dynamic hedging. The idea is to construct a portfolio of European options that replicate the conditional expected GMWB liability in a short time period, and update the portfolio after the options expire. This strategy requires fewer portfolio adjustments, and outperforms the dynamic strategy when there are random jumps in the underlying price. We also extend the semi-static hedging strategies to the Heston stochastic volatility model.

Developers are often faced with the task of implementing new features or diagnosing problems in large software systems. Convoluted control and data flows in large object-oriented software systems, however, make even simple tasks extremely difficult, time-consuming, and frustrating. Specifically, Java programs manipulate objects by adding and removing them from collections and by putting and getting them from other objects' fields. Complex object histories hinder program understanding by forcing software maintainers to track the provenance of objects through their past histories when diagnosing software faults. In this thesis, we present a novel approach which answers queries about the evolution of objects throughout their lifetime in a program. On-demand answers to object history queries aids the maintenance of large software systems by allowing developers to pinpoint relevant details quickly. We describe an event-based, flow-insensitive, interprocedural program analysis technique for computing object histories and answering history queries. Our analysis technique identifies all relevant events affecting an object and uses pointer analysis to filter out irrelevant events. It uses prior knowledge of the meanings of methods in the Java collection classes to improve the quality of the histories. We present the details of our technique and experimental results that highlight the utility of object histories in common programming tasks.

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