Verification and validation in software product line engineering

Verification and Validation (V&V) is currently performed during application development for many systems, especially safety-critical and mission-critical systems. However, the V&V process has been limited to single system development. This dissertation describes the extension of V&V from an individual application system to a product line of systems that are developed within an architecture-based software engineering environment.;In traditional V&V, the system provides the context under which the software will be evaluated, and V&V activities occur during all phases of the system development lifecycle. The transition to a product line approach to development removes the individual system as the context for evaluation, and introduces activities that are not directly related to a specific system. This dissertation presents an approach to V&V of software product lines that uses the domain model and the domain architecture as the context for evaluation, and enables V&V to be performed throughout the modified lifecycle introduced by domain engineering.;This dissertation presents three advances that assist in the adaptation of V&V from single application systems to a product line of systems. The first is a framework for performing V&V that includes the activities of traditional application-level V&V, and extends these activities into domain engineering and into the transition between domain engineering and application engineering. The second is a detailed method to extend the crucial V&V activity of criticality analysis from single system development to a product line of systems. The third advance is an approach to enable formal reasoning, which is needed for high assurance systems, on systems that are based on commercial-off-the-shelf (COTS) products

Säätömenetelmien suunnittelu ja toteutus lämmitysprosessiin

Tiivistelmä. Diplomityön tavoitteena oli kehittää ja tutkia säätömenetelmiä itsenäiseen, ja avoimen lähdekoodin ratkaisuja käyttävään säätöjärjestelmään. Tarkasteltaviksi säätömenetelmiksi valittiin perinteinen PID-säätö, sumea säätö ja mallipohjainen säätö. Työn tavoitteena oli myös toteuttaa ensimmäinen versio järjestelmästä. Työn kirjallisuusosa sisältää esittelyn ylätason säätöön ja säätöjärjestelmiin liittyvistä käsitteistä ja periaatteista. Teollisuudessa yleisien hajautettujen ohjausjärjestelmien rakenne ja ylätason optimoinnin merkitys automaatiossa on sisällytetty kirjallisuusosaan lyhyesti. Kirjallisuusosassa esitellään myös kokeellisessa osiossa toteutetut säätömenetelmät, sekä etsittiin niiltä vaadittavia ominaisuuksia skaalautuvuuden ja joustavuuden mahdollistamiseksi. Säätömenetelmien suorituskykyä arvioitiin testausympäristössä toteutetuissa säätötesteissä. Järjestelmä toimi testeissä hyvin, ja jatkokehityksen jälkeen sen siirtämistä tuotantoon voidaan suunnitella. Kolmen toimi- ja mittalaitteen prosessissa testausympäristön lämmitysvastusten tuottama ristikkäisvaikutus vaikuttaa takaisinkytkettyjen säätimien toimintaan. Mallipohjaisen säätimen sisältämä järjestelmän dynamiikkaa kuvaava malli mahdollistaa ristikkäisvaikutusten huomioimisen yksinkertaisella tavalla, joka ilmenee muita säätömenetelmiä pienempinä ylityksinä. Säätömenetelmien vertailuluku kolmen toimi- ja mittalaitteen säätötestissä PI-säätimellä keskineliövirhe oli 188,56 ºC2, sumealla PI-säätimellä keskineliövirhe oli 170,24 ºC2 ja mallipohjaisella säätimellä keskineliövirhe oli 166,37 ºC2.Design of control methods and implementation in the heating process. Abstract. The goal of this master’s thesis was to develop and study control methods for independent control system that uses open source solutions. The control methods studied were traditional PID control, fuzzy control and model predictive control. Another goal was also to implement the first version of this control system. In theory part of the thesis, concepts and principles related to advanced process control and controls systems are reviewed. The structure of distributed control systems common in industry and the importance of upper-level optimization related to process automation are briefly discussed in the theory. Required characteristics of the control methods and control system were examined to enable scalability and flexibility. Also, theory of the control methods implemented in experimental part of the thesis are included. The performance of the developed control methods was evaluated in the testing process. The control system performed successfully in the tests and after further development it can be planned to be used in production. In the process of three controlled and manipulated variables, the coupling effect related to the heating resistances of the testing environment affects the operation of the feedback controllers. The dynamic model used in the model predictive controller enables coupling effects between process variables to be taken into account in a simple way. The model predictive control manifests itself as a smaller overshoot than other tested control methods. The mean squared error values for the control methods in the control test of three controlled and manipulated variables were 188,56 ºC2, 170,24 ºC2 and 166,37 ºC2 for the PI controller, the fuzzy PI controller and the model predictive controller, respectively

Proceedings of the Twenty-Third Annual Software Engineering Workshop

The Twenty-third Annual Software Engineering Workshop (SEW) provided 20 presentations designed to further the goals of the Software Engineering Laboratory (SEL) of the NASA-GSFC. The presentations were selected on their creativity. The sessions which were held on 2-3 of December 1998, centered on the SEL, Experimentation, Inspections, Fault Prediction, Verification and Validation, and Embedded Systems and Safety-Critical Systems

Parameterized Programming and Software Architecture

: This paper discusses an approach to software architecture based on concepts from parameterized programming, particularly its language of "module expressions." A module expression describes the architecture of a system as an interconnection of component modules, and executing the expression actually builds the system. Language features include: modules parameterized by theories, which declare interfaces; a number of module composition operations; views for binding modules to interfaces; and both vertical and horizontal composition. Modules may involve information hiding, theories may declare semantic restrictions with axioms, and views assert behavioral satisfaction of axioms by a module. Some "laws of software composition" are given, showing how various module composition operations are related. We also show how a variety of architectural styles can be supported, and how this approach can be extended to support evolution and traceability. All this is intended to ease the development ..