Failures from the Environment, a Report on the First FAILSAFE workshop

This document presents the views expressed in the submissions and discussions at the FAILSAFE workshop about the common problems that plague embedded sensor system deployments in the wild. We present analysis gathered from the submissions and the panel session of the FAILSAFE 2017 workshop held at the SenSys 2017 conference. The FAILSAFE call for papers specifically asked for descriptions of wireless sensor network (WSN) deployments and their problems and failures. The submissions, the questions raised at the presentations, and the panel discussion give us a sufficient body of work to review, and draw conclusions regarding the effect that the environment has as the most common cause of embedded sensor system failures

The entropy reduction engine: Integrating planning, scheduling, and control

The Entropy Reduction Engine, an architecture for the integration of planning, scheduling, and control, is described. The architecture is motivated, presented, and analyzed in terms of its different components; namely, problem reduction, temporal projection, and situated control rule execution. Experience with this architecture has motivated the recent integration of learning. The learning methods are described along with their impact on architecture performance

Engineering Trustworthy Self-Adaptive Software with Dynamic Assurance Cases

Building on concepts drawn from control theory, self-adaptive software handles environmental and internal uncertainties by dynamically adjusting its architecture and parameters in response to events such as workload changes and component failures. Self-adaptive software is increasingly expected to meet strict functional and non-functional requirements in applications from areas as diverse as manufacturing, healthcare and finance. To address this need, we introduce a methodology for the systematic ENgineering of TRUstworthy Self-adaptive sofTware (ENTRUST). ENTRUST uses a combination of (1) design-time and runtime modelling and verification, and (2) industry-adopted assurance processes to develop trustworthy self-adaptive software and assurance cases arguing the suitability of the software for its intended application. To evaluate the effectiveness of our methodology, we present a tool-supported instance of ENTRUST and its use to develop proof-of-concept self-adaptive software for embedded and service-based systems from the oceanic monitoring and e-finance domains, respectively. The experimental results show that ENTRUST can be used to engineer self-adaptive software systems in different application domains and to generate dynamic assurance cases for these systems

Profile of a cell test database and a corresponding reliability database

The development of computerized control, and data retrieval for aerospace cell testing affords an excellent opportunity to incorporate three specific concepts to both manage the test area and to track product performance on a real-time basis. The adoption and incorporation of precepts fostered by this total quality management (TQM) initiative are critical to us for retaining control of our business while substantially reducing the separate quality control inspection activity. Test discrepancies are all 'equally bad' in cell acceptance testing because, for example, we presently do not discriminate between 1 or 25 mV for an overvoltage condition. We must take leadership in classifying such discrepancies in order to expedite their clearance and redirect our resources for prevention activities. The development and use of engineering alerts (or guardbanding) which more closely match our product capabilities and are toleranced tighter than the required customer specification are paramount to managing the test unit in order to remain both quality and cost effective

The blind leading the blind: Mutual refinement of approximate theories

The mutual refinement theory, a method for refining world models in a reactive system, is described. The method detects failures, explains their causes, and repairs the approximate models which cause the failures. The approach focuses on using one approximate model to refine another

Runtime observable and adaptable UML state machine-based software components generation and verification: [email protected] approach

Cyber-Physical Systems (CPSs) are embedded computing systems in which computation interacts closely with the physical world through sensors and actuators. CPSs are used to control context aware systems. These types of systems are complex systems that will have different configurations and their control strategy can be configured depending the environmental data and current situation of the context. Therefore, in current industrial environments, the software of embedded and Cyber-Physical systems have to cope with increasing complexity, uncertain scenarios and safe requirements at runtime. The UML State Machine is a powerful formalism to model the logical behaviour of these types of systems, and in Model Driven Engineering (MDE) we can generate code automatically from these models. MDE aims to overcome the complexity of software construction by allowing developers to work at the high-level models of software systems instead of low-level codes. However, determining and evaluating the runtime behaviour and performance of models of CPSs using commercial MDE tools is a challenging task. Such tools provide little support to observe at model-level the execution of the code generated from the model, and to collect the runtime information necessary to, for example, check whether defined safe properties are met or not. One solution to address these requirements is having the software components information in model terms at runtime ([email protected]). Work on [email protected] seeks to extend the applicability of models produced in MDE approaches to the runtime environment. Having the model at runtime is the first step towards the runtime verification. Runtime verification can be performed using the information of model elements (current state, event, next state,etc.) This thesis aims at advancing the current practice on generating automatically Unified Modeling Language - State Machine (UML-SM) based software components that are able to provide their internal information in model terms at runtime. Regarding automation, we propose a tool supported methodology to automatically generate these software components. As for runtime monitoring, verification and adaptation, we propose an externalized runtime module that is able to monitor and verify the correctness of the software components based on their internal status in model terms at component and system level. In addition, if an error is detected, the runtime adaptation module is activated and the safe adaptation process starts in the involved software components. All things considered, the overall safe level of the software components and CPSs is enhanced.Sistema Ziber-Fisikoak, konputazio sistema txertatuez osatuta daude. Konputazio sistema txertatu hauek, mundu birtuala mundu fisikoarekin uztartzeko gaitasuna eskaintzen dute. Sistema ziberfisikoak orokorrean sistema konplexuak izan ohi dira eta inguruan gertazen denaren araberako konfigurazio desberdinak izan ohi dituzte. Gaur egungo industria ingurunetan, sistema hauek daramaten kontroleko softwarea asko handitu da eta beren konplexutasunak ere gorakada handia izan du: aurrez ezagunak ez diren baldintza eta inguruetan lan egin beharra dute askotan, denbora errealeko eskakizunak eta segurtasun eskakizunak ere beteaz. UML State Machine formalismoa, goian aipaturiko sistema mota horien portaera logikoa modelizatzeko erabiltzen den formalismo indartsu bat da. Formalismo honen baitan eta Model Driven Engineering (MDE) enfokea jarraituaz, sistema modelatzeko erabilitako grafikoetatik sisteman txertatua izango den kodea automatikoki sor genezake. MDEk softwarea sortzeko orduan izan genezakeen konplexutasuna gainditu nahi du, garatzailei software-sistemen goi-mailako ereduetan lan egiteko aukera emanez. Hala ere, MDE-an oinarrituriko tresna komertzialak erabiliaz, zaila izaten da berauen bidez sorturiko kodearen errendimendua eta portaera sistema exekuzioan dagoenean ebaluatzea. Tresna horiek laguntza gutxi eskaintzen dute modelotatik sortutako kodea exekutatzen ari denean sisteman zer gertatzen ari denaren informazioa modeloaren terminoetan jasotzeko. Beraz, exekuzio denboran, oso zaila izaten da sistemaren portaera egokia den edo ez aztertzea modelo mailako informazio hori erabiliaz. Eskakizun horiek kudeatzeko modu bat, software modeloaren informazioa denbora errealean izatea da ([email protected] enfokea). [email protected] enfokearen helburu nagusietako bat, MDE enfokearekin garapen fasean sortutako modeloak exekuzio denboran (runtime-en) erabilgarri izatean datza. Exekuzio denboran egiaztapen edo testing-a egin ahal izateko lehen urratsa, testeatu nahi den software horren modeloa exekuzio denboran eskuragarri izatea da. Honela, exekuzio denborako egiaztapen edo berifikazioak softwarea modelatzeko erabili ditugun elementu berberak erabiliaz egin daitke (egungo egoera, gertaera, hurrengo egoera, eta abar). Tesi honen helburutako bat UML-State Machine modeloetan oinarritutako eta exekuzio denboran beren barne egoeraren informazioa modeloko elementu bidez probestu ahalko duten software osagaiak modu automatikoan sortzea da. Automatizazioari dagokionez, lehenik eta behin, software-osagai horiek automatikoki sortzen dituzten tresnak eskaintzen dituen metodologia proposatzen dugu. Bigarrenik, UMLSM oinarritutako software osagaiak automatikoki sortuko dituen herraminta bera proposatzen dugu. Exekuzio denboran eguneraketen jarraipenari, egiaztatzeari eta egokitzeari dagokionez, barne egoera UML-SM modelo terminoetan eskaintzen duten software osagaiak egiaztatzeko eta egokitzeko gai den kanpo exekuzio modulo bat proposatzen dugu. Honela, errore bat detektatzen bada, exekuzio garaian egokitze modulua aktibatuko da egokitzapen prozesu segurua martxan jarriaz. Honek, dagokion software osagaiari abixua bidaliko dio egokitzapena egin dezan. Gauza guztiak kontuan hartuta, software osagaien eta CPSen segurtasun maila orokorra hobetua izango da.Los sistemas cyber-físicos (CPSs) son sistemas de computación embebidos en los que la computación interactúa estrechamente con el mundo físico a través de sensores y actuadores. Los CPS se utilizan para controlar sistemas que proveen conocimiento del contexto. Este tipo de sistemas son sistemas complejos que suelen tener diferentes configuraciones y su estrategia de control puede configurarse en función de los datos del entorno y de la situación actual del contexto. Por lo tanto, en los entornos industriales actuales, el software de los sistemas embebidos tiene que hacer frente a la creciente complejidad, los escenarios inciertos y los requisitos de seguridad en tiempo de ejecución. Las máquinas de estado UML son un formalismo muy utilizado en industria para modelar el comportamiento lógico de este tipo de sistemas, y siguiendo el enfoque Model Driven Engineering (MDE) podemos generar código automáticamente a partir de estos modelos. El objetivo de MDE es superar la complejidad de la construcción de software permitiendo a los desarrolladores trabajar en los modelos de alto nivel de los sistemas de software en lugar de tener que codificar el control mediante lenguajes de programación de bajo nivel. Sin embargo, determinar y evaluar el comportamiento y el rendimiento en tiempo de ejecución de estos modelos generados mediante herramientas comerciales de MDE es una tarea difícil. Estas herramientas proporcionan poco apoyo para observar a nivel de modelo la ejecución del código generado a partir del modelo. Por lo tanto, no son muy adecuadas para poder recopilar la información de tiempo de ejecución necesaria para, por ejemplo, comprobar si se cumplen o no las restricciones definidas. Un enfoque para gestionar estos requisitos, es tener la información de los componentes de software en términos de modelo en tiempo de ejecución ([email protected]). El trabajo en [email protected] busca ampliar la aplicabilidad de los modelos producidos en fase de desarrollo mediante el enfoque MDE al entorno de tiempo de ejecución. Tener el modelo en tiempo de ejecución es el primer paso para poder llevar a cabo la verificación en tiempo de ejecución. Así, esta verificación se podrá realizar utilizando la información de los elementos del modelo (estado actual, evento, siguiente estado, etc.). El objetivo de esta tesis es avanzar en la práctica actual de generar automáticamente componentes software basados en Unified Modeling Language - State Machine (UML-SM) que sean capaces de proporcionar información interna en términos de modelos en tiempo de ejecución. En cuanto a la automatización, en primer lugar, proponemos una metodología soportada por herramientas para generar automáticamente estos componentes de software. En segundo lugar, proponemos un marco de trabajo de generación de componentes de software basado en UML-SM. En cuanto a la monitorización, verificación y adaptación en tiempo de ejecución, proponemos un módulo de tiempo de ejecución externalizado que es capaz de monitorizar y verificar la validez de los componentes del software en función de su estado interno en términos de modelo. Además, si se detecta un error, se activa el módulo de adaptación en tiempo de ejecución y se inicia el proceso de adaptación seguro en el componente de software correspondiente. Teniendo en cuenta todo esto, el nivel de seguridad global de los componentes del software y de los CPS se ve mejorado

Operational results for the experimental DOE/NASA Mod-OA wind turbine project

The Mod-OA wind turbine project which was to gain early experience in the operation of large wind turbines in a utility environment is discussed. The Mod-OA wind turbines were a first generation design, and even though not cost effective, the operating experience and performance characteristics had a significant effect on the design and development of the second and third generation machines. The Mod-OA machines were modified as a result of the operational experience, particularly the blade development and control system strategy. The results of study to investigate the interaction of a Mod-OA wind turbine with an isolated diesel generation system are discussed. The machine configuration, its advantages and disadvantages and the machine performance and availability are discussed