Construction of formal models and verifying property specifications through an example of railway interlocking systems

Abstract The use of formal modeling has seen an increasing interest in the development of safety-critical, embedded microcomputer-controlled railway interlocking systems, due to its ability to specify the behavior of the systems using mathematically precise rules. The research goal is to prepare a specification-verification environment, which supports the developer of the railway interlocking systems in the creation of a formally-proven correct design and at the same time hides the inherent mathematical-computer since related background knowledge. The case study is presented with the aim to summarize the process of formalizing a domain specification, and to show further application possibilities (e.g. verification methods)

Formal Modeling and Verification of the Functionality of Electronic Urban Railway Control Systems Through a Case Study

This paper presents a formal model-based methodology to support railway engineers in the design of safe electronic urban railway control systems. The purpose of our research is to overcome the deficiencies of existing traditional design methodologies, namely the incompleteness and the potential presence of contradictions in the system specification resulting from non-formal development techniques. We illustrate the application of the methodology via a case study of a tram-road level crossing protection system. It was chosen partly because it has a simple architecture and a small number of elements, thus it fits the scope limitations of this article. At the same time, it is suitable for presenting all essential features of our methodology. The proposed solution provides a specification/verification environment that facilitates the construction of correct, complete, consistent, and verifiable functional specifications during the development, while hiding all the formal method-related details from the railway engineers writing the specifications. Using this formal model-based methodology, a high-quality functional specification can be achieved, which is guaranteed to be more exhaustive and will contain fewer errors than traditional development

Energetikai és környezetvédelmi rendszerek kísérleti és számítástechnikai modellezésének és a vonatkozó szerkezetek és folyamatok optimálásának összekapcsolása = Connection between experimental and numerical modelling of power engineering and environmental protection system and the optimisation of related processes and structures

A pályázat keretében elkészült több áramlási és hőtani berendezésben lejátszódó energetikai folyamat numerikus modellezése és jelentős részüknél az üzemük, illetve a kialakításuk optimálása. Ezek: 1. Ipari üzemcsarnokok szellőzésének és a szennyeződés épületen kívüli tovaterjedésének modellezése, a szellőzés optimálása 2. Spirális hőcserélők optimális kialakításának elemzése a. Síkbeli spirális hőcserélő modellezése b. Villamos fűtésű spirális hőcserélő modellezése c. Lapos lángú égővel fűtött spirális hőcserélő modellezése és üzemének optimálása 3. Hőkezelő kemencék gázcirkulációjának modellezése és optimálása a. Kísérleti kemence hőtechnikai modellezése b. Villamos fűtésű alagútkemence modellezése c. Hőkezelő csőkemence modellezése és a kemence, illetve a tüzelés optimálása 4. Elszívóhálózatok modellezése, kialakításuk és üzemük optimálása 5. Villamosan fűtött fémszál körüli áramlás modellezése Az optimálások a Dynamic_Q eljárással és genetikus algoritmus felhasználásával készültek. A számítási eredmények validálására irodalmi adatokat, saját üzemi és laboratóriumi méréseinket használtuk fel. A kutatás végeredményeként kialakult egy olyan eljárás, amelynek segítségével a legkülönbözőbb áramlási- és hőtani folyamat FLUENT programrendszerben történő numerikus modellezése és a matematikai optimálás összekapcsolható. A módszert kiterjesztettük saját kódú numerikus eljárás optimálási eljárásba való beépítésére is. | Within this OTKA research project several tasks were carried out. Analysis and numerical modelling of flow and thermal process in equipments were done, and in some cases their shape or the operation efficiency were optimised too. These works were the following: 1. Numerical modelling and optimisation of natural ventilation of industrial workshops, 2. Numerical modelling of spread and dispersion of air-pollution outside a workshop, 3. Analysis of spiral heat-exchanger for optimal shape (a 2D spiral heat-exchanger, a 3D spiral heat-exchanger with electric heat, and one heated with a flat-flamed burner). 4. Modelling and optimising the gas circulation of heat-treating furnaces (an experimental furnace, an electrically heated tunnel furnace, a heat-treating pipe-furnace). 5. Modelling air-sucking networks, optimization of their shape and operation. 6. Flow modelling around an electrically heated wire. The optimisation tasks were carried out by using the Dynamic-Q and the Genetic Algorithm separately. For validating the computations own experimental (laboratory) and operational (on site) measurements were used as well as data of technical literature. As the result of the research a new method have been developed, by which the numerical simulation (modelling) of any flow and thermal process with the FLUENT software package can be coupled with mathematical optimisation. The method was extended also for coupling the optimization algorithm with home-made numerical code

Multicopy metrology with many-particle quantum states

We consider quantum metrology with several copies of bipartite and multipartite quantum states. We characterize the metrological usefulness by determining how much the state outperforms separable states. We identify a large class of entangled states that become maximally useful for metrology in the limit of infinite number of copies. The maximally achievable metrological usefulness is attained exponentially fast in the number of copies. We show that, on the other hand, pure entangled states with even a small amount of white noise do not become maximally useful even in the limit of infinite number of copies. We also make general statements about the usefulness of a single copy of pure entangled states. We show that the multiqubit states presented in Hyllus et al. [Phys. Rev. A 82, 012337 (2010)], which are not useful, become useful if we embed the qubits locally in qutrits. We discuss the relation of our scheme to error correction, and possible use for quantum information processing in a noisy environment.Comment: 7 pages including 3 figures + 5-page supplement including 2 figures, revtex4.

Activation of metrologically useful genuine multipartite entanglement

We consider quantum metrology with several copies of bipartite and multipartite quantum states. We characterize the metrological usefulness by determining how much the state outperforms separable states. We identify a large class of entangled states that become maximally useful for metrology in the limit of large number of copies, even if the state is weakly entangled and not even more useful than separable states. This way we activate metrologically useful genuine multipartite entanglement. Remarkably, not only that the maximally achievable metrological usefulness is attained exponentially fast in the number of copies, but it can be achieved by the measurement of few simple correlation observables. We also make general statements about the usefulness of a single copy of pure entangled states. We surprisingly find that the multiqubit states presented in Hyllus et al (2010 Phys. Rev. A 82 012337), which are not useful, become useful if we embed the qubits locally in qutrits. We discuss the relation of our scheme to error correction, and its possible use for quantum metrology in a noisy environment