A multi-paradigm language for reactive synthesis

This paper proposes a language for describing reactive synthesis problems that integrates imperative and declarative elements. The semantics is defined in terms of two-player turn-based infinite games with full information. Currently, synthesis tools accept linear temporal logic (LTL) as input, but this description is less structured and does not facilitate the expression of sequential constraints. This motivates the use of a structured programming language to specify synthesis problems. Transition systems and guarded commands serve as imperative constructs, expressed in a syntax based on that of the modeling language Promela. The syntax allows defining which player controls data and control flow, and separating a program into assumptions and guarantees. These notions are necessary for input to game solvers. The integration of imperative and declarative paradigms allows using the paradigm that is most appropriate for expressing each requirement. The declarative part is expressed in the LTL fragment of generalized reactivity(1), which admits efficient synthesis algorithms, extended with past LTL. The implementation translates Promela to input for the Slugs synthesizer and is written in Python. The AMBA AHB bus case study is revisited and synthesized efficiently, identifying the need to reorder binary decision diagrams during strategy construction, in order to prevent the exponential blowup observed in previous work.Comment: In Proceedings SYNT 2015, arXiv:1602.0078

Theoretical Studies in Solar Cell Physics

Paper VI is excluded from the dissertation until it will be published.In this thesis, we develop analytical models with the purpose of expanding knowledge and gaining understanding of some of the internal mechanisms that limit the efficiency of single-junction solar cells. We focus on three distinct topics: fundamental energy losses, the temperature sensitivity of single-junction solar cells and the effect of the series resistance on the maximum power point. The thesis is divided in two parts. The first part reviews basic solar cell physics topics and introduces some more advanced concepts to provide the reader with the necessary background to understand the attached papers. The latter constitute the second part of the thesis.publishedVersio

Non-linear model predictive energy management strategies for stand-alone DC microgrids

Due to substantial generation and demand fluctuations in stand-alone green micro-grids, energy management strategies (EMSs) are becoming essential for the power sharing purpose and regulating the microgrids voltage. The classical EMSs track the maximum power points (MPPs) of wind and PV branches independently and rely on batteries, as slack terminals, to absorb any possible excess energy. However, in order to protect batteries from being overcharged by realizing the constant current-constant voltage (IU) charging regime as well as to consider the wind turbine operational constraints, more flexible multivariable and non-linear strategies, equipped with a power curtailment feature, are necessary to control microgrids. This dissertation work comprises developing an EMS that dynamically optimises the operation of stand-alone dc microgrids, consisting of wind, photovoltaic (PV), and battery branches, and coordinately manage all energy flows in order to achieve four control objectives: i) regulating dc bus voltage level of microgrids; ii) proportional power sharing between generators as a local droop control realization; iii) charging batteries as close to IU regime as possible; and iv) tracking MPPs of wind and PV branches during their normal operations. Non-linear model predictive control (NMPC) strategies are inherently multivariable and handle constraints and delays. In this thesis, the above mentioned EMS is developed as a NMPC strategy to extract the optimal control signals, which are duty cycles of three DC-DC converters and pitch angle of a wind turbine. Due to bimodal operation and discontinuous differential states of batteries, microgrids belong to the class of hybrid dynamical systems of non-Filippov type. This dissertation work involves a mathematical approximation of stand-alone dc microgrids as complementarity systems (CSs) of Filippov type. The proposed model is used to develop NMPC strategies and to simulate microgrids using Modelica. As part of the modelling efforts, this dissertation work also proposes a novel algorithm to identify an accurate equivalent electrical circuit of PV modules using both standard test condition (STC) and nominal operating cell temperature (NOCT) information provided by manufacturers. Moreover, two separate stochastic models are presented for hourly wind speed and solar irradiance levels

Model Checking Cyber-Physical Systems

2017 - 2018Cyber-Physical Systems (CPSs) are integrations of computation with physical processes. Applications of CPS arguably have the potential to overshadow the 20-th century IT revolution. Nowadays, CPSs application to many sectors like Smart Grids, Transportation, and Health help us run our lives and businesses smoothly, successfully and safely. Since malfunctions in these CPSs can have serious, expensive, sometimes fatal consequences, Simulation-based Veri cation (SBV) tools are vital to minimize the probability of errors occurring during the development process and beyond. Their applicability is supported by the increasingly widespread use of Model Based Design (MBD) tools. MBD enables the simulation of CPS models in order to check for their correct behaviour from the very initial design phase. The disadvantage is that SBV for complex CPSs is an extremely resources and time-consuming process, which typically requires several months of simulation. Current SBV tools are aimed at accelerating the veri cation process with mul- tiple simulators working simultaneously. To this end, they compute all the scenarios in advance in such a way as to split and simulate them in parallel. Nevertheless, there are still limitations that prevent a more widespread adop- tion of SBV tools. To this end, we present a MBD methodology aiming the acausual modeling and veri cation via formal-methods, speci cally the model checking techniques, the system under veri cation (SUV). Our approach relies basically on: Firstly, the analysis of the steady-states of the CPS and the bound- ing technique of the system's state in parallel with the simulation in order to identify the state space of the system simulating it only once, then represent it as a Finite State Machine (FSM). Secondly, exhaustively verify the resulted FSM using a symbolic model checker and express the desired properties in classical temporal logic. The application to a power management system is presented as a case study. [edited by Author]XXX cicl

Aspects of the Grammar of Eastern Khanty

A reference grammar of the endangered indigenous dialects of Vasyugan and Alexandrovo Eastern Khanty of the Uralic language family is the study based on the corpus of natural narrative discourse, and is set in a general cognitive -functional paradigm. The description addresses the main patterns of the Eastern Khanty language system and offers typological contextualization of the reviewed language data. The description covers the issues in phonology (backness vowel harmony, consonant-vowel harmony), word-classes, morphology (derivation and inflection), syntax and semantics of simple and complex clauses (typical SOV patterns with occasional non-canonical argument ergative marking against the general background of Nom-Acc system and robust use of non-finite and finite constructions as relative, adverbial and complement clauses)

Spent nuclear fuel project high-level information management plan

This document presents the results of the Spent Nuclear Fuel Project (SNFP) Information Management Planning Project (IMPP), a short-term project that identified information management (IM) issues and opportunities within the SNFP and outlined a high-level plan to address them. This high-level plan for the SNMFP IM focuses on specific examples from within the SNFP. The plan`s recommendations can be characterized in several ways. Some recommendations address specific challenges that the SNFP faces. Others form the basis for making smooth transitions in several important IM areas. Still others identify areas where further study and planning are indicated. The team`s knowledge of developments in the IM industry and at the Hanford Site were crucial in deciding where to recommend that the SNFP act and where they should wait for Site plans to be made. Because of the fast pace of the SNFP and demands on SNFP staff, input and interaction were primarily between the IMPP team and members of the SNFP Information Management Steering Committee (IMSC). Key input to the IMPP came from a workshop where IMSC members and their delegates developed a set of draft IM principles. These principles, described in Section 2, became the foundation for the recommendations found in the transition plan outlined in Section 5. Availability of SNFP staff was limited, so project documents were used as a basis for much of the work. The team, realizing that the status of the project and the environment are continually changing, tried to keep abreast of major developments since those documents were generated. To the extent possible, the information contained in this document is current as of the end of fiscal year (FY) 1995. Programs and organizations on the Hanford Site as a whole are trying to maximize their return on IM investments. They are coordinating IM activities and trying to leverage existing capabilities. However, the SNFP cannot just rely on Sitewide activities to meet its IM requirements. While the SNFP can use some work done Sitewide and by projects such as the Tank Waste Remediation System (TWRS), they will still need to make some IM investments of their own