The Potential and Challenges of CAD with Equational Constraints for SC-Square

Cylindrical algebraic decomposition (CAD) is a core algorithm within Symbolic Computation, particularly for quantifier elimination over the reals and polynomial systems solving more generally. It is now finding increased application as a decision procedure for Satisfiability Modulo Theories (SMT) solvers when working with non-linear real arithmetic. We discuss the potentials from increased focus on the logical structure of the input brought by the SMT applications and SC-Square project, particularly the presence of equational constraints. We also highlight the challenges for exploiting these: primitivity restrictions, well-orientedness questions, and the prospect of incrementality.Comment: Accepted into proceedings of MACIS 201

Program Verification in the presence of complex numbers, functions with branch cuts etc

In considering the reliability of numerical programs, it is normal to "limit our study to the semantics dealing with numerical precision" (Martel, 2005). On the other hand, there is a great deal of work on the reliability of programs that essentially ignores the numerics. The thesis of this paper is that there is a class of problems that fall between these two, which could be described as "does the low-level arithmetic implement the high-level mathematics". Many of these problems arise because mathematics, particularly the mathematics of the complex numbers, is more difficult than expected: for example the complex function log is not continuous, writing down a program to compute an inverse function is more complicated than just solving an equation, and many algebraic simplification rules are not universally valid. The good news is that these problems are theoretically capable of being solved, and are practically close to being solved, but not yet solved, in several real-world examples. However, there is still a long way to go before implementations match the theoretical possibilities

Q(sqrt(-3))-Integral Points on a Mordell Curve

We use an extension of quadratic Chabauty to number fields,recently developed by the author with Balakrishnan, Besser and M ̈uller,combined with a sieving technique, to determine the integral points overQ(√−3) on the Mordell curve y2 = x3 − 4

Third International Conference on Technologies for Music Notation and Representation TENOR 2017

The third International Conference on Technologies for Music Notation and Representation seeks to focus on a set of specific research issues associated with Music Notation that were elaborated at the first two editions of TENOR in Paris and Cambridge. The theme of the conference is vocal music, whereas the pre-conference workshops focus on innovative technological approaches to music notation

Foundations of Software Science and Computation Structures

This open access book constitutes the proceedings of the 23rd International Conference on Foundations of Software Science and Computational Structures, FOSSACS 2020, which took place in Dublin, Ireland, in April 2020, and was held as Part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2020. The 31 regular papers presented in this volume were carefully reviewed and selected from 98 submissions. The papers cover topics such as categorical models and logics; language theory, automata, and games; modal, spatial, and temporal logics; type theory and proof theory; concurrency theory and process calculi; rewriting theory; semantics of programming languages; program analysis, correctness, transformation, and verification; logics of programming; software specification and refinement; models of concurrent, reactive, stochastic, distributed, hybrid, and mobile systems; emerging models of computation; logical aspects of computational complexity; models of software security; and logical foundations of data bases.

Design and modelling of innovative machinery systems for large ships

Eighty percent of the growing global merchandise trade is transported by sea. The shipping industry is required to reduce the pollution and increase the energy efficiency of ships in the near future. There is a relatively large potential for approaching these requirements by implementing waste heat recovery (WHR) systems.Studies of alternative WHR systems in other applications suggests that the Kalina cycle and the organic Rankine cycle (ORC) can provide significant advantages over the steam Rankine cycle, which is currently used for marine WHR.This thesis aims at creating a better understanding of the Kalina cycle and the ORC in the application on board large ships; the thermodynamic performances of the mentioned power cycles are compared. Recommendations of suitable system layouts and working fluids for the marine applications are provided along with methodologies useful for the design and optimisation of the main engine and WHR system combined cycle.Numerical models of a low-speed two-stroke diesel engine, turbochargers, and the mentioned types of WHR systems in various configurations, are used to achieve the mentioned objectives. The main engine is simulated using a zero-dimensional model consisting of a two-zone combustion and NOx emission model, a double Wiebe heat release model, the Redlich-Kwong equation of state and the Woschni heat loss correlation. A novel methodology is presented and used to determine the optimum organic Rankine cycle process layout, working fluid and process parameters for marine WHR. Using this mentioned methodology, regression models are derived for the prediction of the maximum obtainable thermal efficiency of ORCs. A unique configuration of the Kalina cycle, the Split-cycle, is analysed to evaluate the fullest potential of the Kalina cycle for the purpose. Integrated with three main engine waste heat streams, the Kalina cycle, the ORC and a dual-pressure steam cycle are compared with regards to the power outputs and other aspects. The part-load performances of four different WHR system configurations, including an exhaust gas recirculation system, are evaluated with regards to the fuel consumption and NOx emissions trade-off.The results of the calibration and validation of the engine model suggest that the main performance parameters can be predicted with adequate accuracies for the overall purpose. The results of the ORC and the Kalina cycle optimisation efforts indicate that both cycles can achieve higher power outputs than the steam cycle; however, the results suggest that for the Kalina cycle to achieve such high power outputs, a relatively complex process layout and high working pressures are required. Conversely, the ORC can achieve superior power outputs with a much simpler process layout in comparison. The toxic ammonia-water working fluid of the Kalina cycle is problematic for the use in marine machinery rooms, and so are the highly flammable ORC working fluids. Based on the analyses, no configuration of the Kalina cycle is recommended for marine WHR. An exhaust gas power turbine is recommended as an initial WHR system investment due its cost-effectiveness. For large ships, a dual-pressure steam cycle is recommended because it is well-known, proven, highly efficient and environmentally benign. The ORC is recommended for large and medium size ships and it is recommended to use the highly flammable working fluids and take the needed precautions. The main reasons are that the ORCs can achieve superior efficiencies with a simple process that can be operated fully automated. For the same reasons a WHR system consisting of a hybrid turbocharger and a recuperated ORC is recommended

Automated Deduction – CADE 28

This open access book constitutes the proceeding of the 28th International Conference on Automated Deduction, CADE 28, held virtually in July 2021. The 29 full papers and 7 system descriptions presented together with 2 invited papers were carefully reviewed and selected from 76 submissions. CADE is the major forum for the presentation of research in all aspects of automated deduction, including foundations, applications, implementations, and practical experience. The papers are organized in the following topics: Logical foundations; theory and principles; implementation and application; ATP and AI; and system descriptions

Foundations of Software Science and Computation Structures

This open access book constitutes the proceedings of the 23rd International Conference on Foundations of Software Science and Computational Structures, FOSSACS 2020, which took place in Dublin, Ireland, in April 2020, and was held as Part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2020. The 31 regular papers presented in this volume were carefully reviewed and selected from 98 submissions. The papers cover topics such as categorical models and logics; language theory, automata, and games; modal, spatial, and temporal logics; type theory and proof theory; concurrency theory and process calculi; rewriting theory; semantics of programming languages; program analysis, correctness, transformation, and verification; logics of programming; software specification and refinement; models of concurrent, reactive, stochastic, distributed, hybrid, and mobile systems; emerging models of computation; logical aspects of computational complexity; models of software security; and logical foundations of data bases.

Investigation of Fore-Aft Element Connectors for an ultra-efficient Slotted, Natural-Laminar-Flow Aircraft Wing

The SNLF [slotted, natural-laminar-flow airfoil] is a revolutionary technology projected to contribute significant decreases in fuel consumption and carbon emissions. The SNLF is designed to allow favorable pressure gradients to extend further aft increasing the extent of laminar flow achievable to about 90% of the entire airfoil, thus reducing the wing profile drag and subsequently fuel consumption. The SNLF is not without its complexity as it introduces several design challenges to maintain laminar flow. The slot width must be maintained during flight to engage the favorable pressure gradients that enable these benefits. As such a crucial aspect for implementing this technology is how the two elements of the slotted airfoil are joined. The slot connectors must be adequately analyzed to transfer the induced high-lift from the aft element while ensuring minimal impedance on the laminar flow within the slot. This dissertation presents the analyses and considerations for the slot connectors including their overall placement within the slot, size, and shape with the effects they have on the structural components of the aircraft half-span wing. Investigations using finite element (FE) modeling, computational fluid dynamics (CFD), and topology optimization inform of potential material distributions and design considerations to ensure the slot connectors transfer the load while maintaining the slot width. To further evaluate potential weight reduction the adhesive joining of composite overlay to a metallic substrate is investigated with the use of non-deterministic approaches including global sensitivity analysis, surrogate modeling, and reduced order modeling