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Journal ArticleDOI

A Contract-Based Methodology for Aircraft Electric Power System Design

TL;DR: A platform-based methodology is proposed, which enables independent implementation of system topology and control protocol by using a compositional approach and is shown to be effective on a proof-of-concept electric power system design.
Abstract: In an aircraft electric power system, one or more supervisory control units actuate a set of electromechanical switches to dynamically distribute power from generators to loads, while satisfying safety, reliability, and real-time performance requirements. To reduce expensive redesign steps, this control problem is generally addressed by minor incremental changes on top of consolidated solutions. A more systematic approach is hindered by a lack of rigorous design methodologies that allow estimating the impact of earlier design decisions on the final implementation. To achieve an optimal implementation that satisfies a set of requirements, we propose a platform-based methodology for electric power system design, which enables independent implementation of system topology (i.e., interconnection among elements) and control protocol by using a compositional approach. In our flow, design space exploration is carried out as a sequence of refinement steps from the initial specification toward a final implementation by mapping higher level behavioral and performance models into a set of either existing or virtual library components at the lower level of abstraction. Specifications are first expressed using the formalisms of linear temporal logic, signal temporal logic, and arithmetic constraints on Boolean variables. To reason about different requirements, we use specialized analysis and synthesis frameworks and formulate assume guarantee contracts at the articulation points in the design flow. We show the effectiveness of our approach on a proof-of-concept electric power system design.
Citations
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Book
Michael R. Lyu1
30 Apr 1996
TL;DR: Technical foundations introduction software reliability and system reliability the operational profile software reliability modelling survey model evaluation and recalibration techniques practices and experiences and best current practice of SRE software reliability measurement experience.
Abstract: Technical foundations introduction software reliability and system reliability the operational profile software reliability modelling survey model evaluation and recalibration techniques practices and experiences best current practice of SRE software reliability measurement experience measurement-based analysis of software reliability software fault and failure classification techniques trend analysis in validation and maintenance software reliability and field data analysis software reliability process assessment emerging techniques software reliability prediction metrics software reliability and testing fault-tolerant SRE software reliability using fault trees software reliability process simulation neural networks and software reliability. Appendices: software reliability tools software failure data set repository.

1,068 citations

Journal ArticleDOI
26 Feb 2015-Sensors
TL;DR: Two projects show that deterministic CPS models with faithful physical realizations are possible and practical and shows that the timing precision of synchronous digital logic can be practically made available at the software level of abstraction.
Abstract: This paper is about better engineering of cyber-physical systems (CPSs) through better models. Deterministic models have historically proven extremely useful and arguably form the kingpin of the industrial revolution and the digital and information technology revolutions. Key deterministic models that have proven successful include differential equations, synchronous digital logic and single-threaded imperative programs. Cyber-physical systems, however, combine these models in such a way that determinism is not preserved. Two projects show that deterministic CPS models with faithful physical realizations are possible and practical. The first project is PRET, which shows that the timing precision of synchronous digital logic can be practically made available at the software level of abstraction. The second project is Ptides (programming temporally-integrated distributed embedded systems), which shows that deterministic models for distributed cyber-physical systems have practical faithful realizations. These projects are existence proofs that deterministic CPS models are possible and practical.

468 citations

Proceedings ArticleDOI
17 Nov 2014
TL;DR: This work describes the use of STL to specify a wide range of properties of these systems, including safety, response and bounded liveness, and encode STL specifications as mixed integer-linear constraints on the system variables in the optimization problem at each step of a model predictive control framework.
Abstract: We present a mathematical programming-based method for model predictive control of discrete-time cyber-physical systems subject to signal temporal logic (STL) specifications. We describe the use of STL to specify a wide range of properties of these systems, including safety, response and bounded liveness. For synthesis, we encode STL specifications as mixed integer-linear constraints on the system variables in the optimization problem at each step of a model predictive control framework. We present experimental results for controller synthesis for building energy and climate control.

375 citations


Cites methods from "A Contract-Based Methodology for Ai..."

  • ...These discrete controllers have successfully been used to construct hybrid controllers for cyber-physical systems in domains including robotics [9] and aircraft power system design [25]....

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Proceedings ArticleDOI
14 Apr 2015
TL;DR: A counterexample-guided inductive synthesis approach to controller synthesis for cyber-physical systems subject to signal temporal logic (STL) specifications, operating in potentially adversarial nondeterministic environments is presented.
Abstract: We present a counterexample-guided inductive synthesis approach to controller synthesis for cyber-physical systems subject to signal temporal logic (STL) specifications, operating in potentially adversarial nondeterministic environments. We encode STL specifications as mixed integer-linear constraints on the variables of a discrete-time model of the system and environment dynamics, and solve a series of optimization problems to yield a satisfying control sequence. We demonstrate how the scheme can be used in a receding horizon fashion to fulfill properties over unbounded horizons, and present experimental results for reactive controller synthesis for case studies in building climate control and autonomous driving.

251 citations


Cites background from "A Contract-Based Methodology for Ai..."

  • ...Approaches that utilize a discrete abstraction enable construction of discrete supervisory controllers, which have successfully been used to construct hybrid controllers for domains including robotics and aircraft power system design; these include approaches that deal with deterministic [17, 23] as well as adversarial environments [10, 27]....

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Journal ArticleDOI
TL;DR: Unless the discussed challenges are satisfactorily addressed and solved, arriving at an AEA that can properly operate over commercial missions will not be possible.
Abstract: Narrow body and wide body aircraft are responsible for more than 75% of aviation greenhouse gas (GHG) emission and aviation, itself, was responsible for about 2.5% of all GHG emissions in the United States in 2018. This situation becomes worse when considering a 4-5% annual growth in air travel. Electrified aircraft is clearly a promising solution to combat the GHG challenge; thus, the trend is to eliminate all but electrical forms of energy in aircraft power distribution systems. However, electrification adds tremendously to the complexity of aircraft electric power systems (EPS), which is dramatically changing in our journey from conventional aircraft to more electric aircraft (MEA) and all electric aircraft (AEA). In this article, we provide an in-depth discussion on MEA/AEA EPS: electric propulsion, distributed propulsion systems (DPS), EPS voltage levels, power supplies, and EPS architectures are discussed. Publications on power flow (PF) analysis and management of EPS are reviewed, and an initial schematic of a potential aircraft EPS with electric propulsion is proposed. In this regard, we also briefly review the components required for MEA/AEA EPS, including power electronics (PE) converters, electric machines, electrochemical energy units, circuit breakers (CBs), and wiring harness. A comprehensive review of each of the components mentioned above or other topics except for those related to steady state power flow in MEA/AEA EPS is out of this article's scope and should be found somewhere else. At the close of the paper, some challenges in the path towards AEA are presented. Unless the discussed challenges are satisfactorily addressed and solved, arriving at an AEA that can properly operate over commercial missions will not be possible.

144 citations


Cites methods from "A Contract-Based Methodology for Ai..."

  • ...Based on the EPS architecture proposed in [62], a platform-based methodology was employed in [63],...

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References
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Proceedings ArticleDOI
30 Sep 1977
TL;DR: A unified approach to program verification is suggested, which applies to both sequential and parallel programs, and the main proof method is that of temporal reasoning in which the time dependence of events is the basic concept.
Abstract: A unified approach to program verification is suggested, which applies to both sequential and parallel programs. The main proof method suggested is that of temporal reasoning in which the time dependence of events is the basic concept. Two formal systems are presented for providing a basis for temporal reasoning. One forms a formalization of the method of intermittent assertions, while the other is an adaptation of the tense logic system Kb, and is particularly suitable for reasoning about concurrent programs.

5,174 citations

Book
25 Apr 2008
TL;DR: Principles of Model Checking offers a comprehensive introduction to model checking that is not only a text suitable for classroom use but also a valuable reference for researchers and practitioners in the field.
Abstract: Our growing dependence on increasingly complex computer and software systems necessitates the development of formalisms, techniques, and tools for assessing functional properties of these systems. One such technique that has emerged in the last twenty years is model checking, which systematically (and automatically) checks whether a model of a given system satisfies a desired property such as deadlock freedom, invariants, and request-response properties. This automated technique for verification and debugging has developed into a mature and widely used approach with many applications. Principles of Model Checking offers a comprehensive introduction to model checking that is not only a text suitable for classroom use but also a valuable reference for researchers and practitioners in the field. The book begins with the basic principles for modeling concurrent and communicating systems, introduces different classes of properties (including safety and liveness), presents the notion of fairness, and provides automata-based algorithms for these properties. It introduces the temporal logics LTL and CTL, compares them, and covers algorithms for verifying these logics, discussing real-time systems as well as systems subject to random phenomena. Separate chapters treat such efficiency-improving techniques as abstraction and symbolic manipulation. The book includes an extensive set of examples (most of which run through several chapters) and a complete set of basic results accompanied by detailed proofs. Each chapter concludes with a summary, bibliographic notes, and an extensive list of exercises of both practical and theoretical nature.

4,905 citations


"A Contract-Based Methodology for Ai..." refers background in this paper

  • ...While in contract-based design the component is regarded as the fundamental element of a design, and systems are denoted as interconnections of components, as we describe the basics of LTL, we prefer to adhere to the classical terminology, which is historically consolidated [23], and define design abstractions in terms of systems....

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  • ...In this section, we consider a version of temporal logic called linear temporal logic (LTL), whose formal semantics can be found in [23]....

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Book ChapterDOI
02 Jan 1991
TL;DR: In this article, a multiaxis classification of temporal and modal logic is presented, and the formal syntax and semantics for two representative systems of propositional branching-time temporal logics are described.
Abstract: Publisher Summary This chapter discusses temporal and modal logic. The chapter describes a multiaxis classification of systems of temporal logic. The chapter describes the framework of linear temporal logic. In both its propositional and first-order forms, linear temporal logic has been widely employed in the specification and verification of programs. The chapter describes the competing framework of branching temporal logic, which has seen wide use. It also explains how temporal logic structures can be used to model concurrent programs using non-determinism and fairness. The chapter also discusses other modal and temporal logics in computer science. The chapter describes the formal syntax and semantics of Propositional Linear Temporal Logic (PLTL). The chapter also describes the formal syntax and semantics for two representative systems of propositional branching-time temporal logics.

2,871 citations

Journal ArticleDOI
Ron Koymans1
TL;DR: This paper characterize real-time systems by giving a classification of such quantitative temporal properties, and extends the usual models for temporal logic by including a distance function to measure time and analyzes what restrictions should be imposed on such a function.
Abstract: This paper is motivated by the need for a formal specification method for real-time systems. In these systemsquantitative temporal properties play a dominant role. We first characterize real-time systems by giving a classification of such quantitative temporal properties. Next, we extend the usual models for temporal logic by including a distance function to measure time and analyze what restrictions should be imposed on such a function. Then we introduce appropriate temporal operators to reason about such models by turning qualitative temporal operators into (quantitative) metric temporal operators and show how the usual quantitative temporal properties of real-time systems can be expressed in this metric temporal logic. After we illustrate the application of metric temporal logic to real-time systems by several examples, we end this paper with some conclusions.

1,230 citations


"A Contract-Based Methodology for Ai..." refers methods in this paper

  • ...For the examples discussed in this paper, we used the Temporal Logic Planning (TuLiP) Toolbox [31], a collection of Python-based code for automatic synthesis of embedded control software, which provides an interface to JTLV....

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  • ...Signal Temporal Logic (STL) [26] has been proposed more recently as a specification language for constraints on real-valued signals in the context of analog and mixed-signal circuits....

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  • ...Parametric Signal Temporal Logic (PSTL) is an extension of STL introduced in [27] to define template formulas containing unknown parameters....

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  • ...To deal with dense-time real signals and hybrid dynamical model that mix the discrete dynamics of the controller with the continuous dynamics of the plant, several logics have been introduced over the years, such as Timed Propositional Temporal Logic [24], andMetric Temporal Logic [25]....

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