A Unified Tool for Performance Modelling and Prediction

Abstract. We describe a novel performability modelling approach which facilitates the efficient solution of performance models extracted from high-level descriptions of systems. The notation which we use for our high-level designs is the UML graphical modelling language. The technology which provides the efficient representation capability for the underlying performance model is the MTBDD-based PRISM probabilistic model checker. The UML models are compiled through an intermediate language, the stochastic process algebra PEPA, before translation into MTBDDs for solution. We illustrate our approach on a real-world analysis problem from the domain of mobile telephony. 1 Introduction Distributed, mobile and global computing environments provide robust development challenges to practising software system developers. Working with rapidlychanging implementation technology means that developers often must spend some of their development time finding and correcting errors in the software libraries and APIs which they use. Fortifying this difficulty is the arduous terrain of dynamic distributed systems where the difficulty of replaying a communication sequence which led to a system fault confounds the process of detecting and correcting implementation errors. In this setting, application developers rarely wish to expend the investment of time which would be needed to build and analyse a performance model of the system which they are developing. The concepts and the modelling languages of performance analysis are relatively unfamiliar to software developers and when already faced with a generous range of other difficulties in the development process, early predictive performance analysis can easily be overlooked

Choreographing security and performance analysis for web services

We describe a UML-based method which supports model-driven development of service-oriented architectures including those used in Web services. Analysable content is extracted from the UML models in the form of process calculus descriptions. These are analysed to provide strong guarantees of satisfactory security and performance. The results are reflected back in the form of a modified version of the UML model which highlights points of the design which can give rise to operational difficulties. A design platform supporting the methodology, Choreographer, interoperates with state-of-the-art UML modelling tools such as Poseidon. We illustrate the approach on an example

Varaston operatiivisen toiminnan kehittäminen

Warehouses have a significant role in improving the value chain between companies. Inefficient warehouses cause longer delivery times and additional costs. Modern methods, information systems and technology can improve the delivery capability and efficiency of warehouses. The purpose of this Master's thesis was to determine the criteria and principles inherent in world-class warehouse logistics and to apply these criteria and principles in a company warehouse to eliminate inefficiencies, such as space utilisation, lack of information, inappropriate stock quantities, missing items at pick up locations, extra handling and searching for items, which are all major problems. The study revealed that order handling time can be reduced by as much as several days and the time utilisation of warehouse personnel can be improved by investing in a warehouse management system. The company could then maintain real-time item quantities at required locations and faster order handling and delivery. Missing items at pickup locations could be resolved by storing a minimum item quantity according to demand. With the use of hand terminals, which control operators between locations, items would no longer need to be searched. Pickup frequency data per items could be used to determine the quantities of stored items, which would make space utilization more efficient. The fact that the warehouse height is 7 meters and pallet height is not constant means that storage automation should be investigated after WMS is successfully underway. Storage automation could realize more efficient floor and height utilization and improve the pick up process.Varastotoimintojen rooli yritysten arvoketjujen virittämisessä on merkittävä. Tehottomasti toimiva varasto aiheuttaa toimitusajan pidentymistä ja ylimääräisiä kustannuksia. Varaston palvelutasoa ja tehokkuutta voidaan parantaa huomattavasti, kun toiminnoissa käytetään nykyaikaisia ohjausperiaatteita, tietojärjestelmiä ja automaatiota. Tässä diplomityössä selvitetään maailman luokan varastologistiikan kriteerit ja periaatteet ja poistetaan näiden avulla erään yrityksen varaston ongelmia. Tilan ahtaus, tiedonkulun puutteet, saldopoikkeamat, puuttuvat tuotteet keruupaikoilla, ylimääräinen varaston järjestely ja tuotteiden etsiminen ovat keskeisimmät ongelmat varastossa. Tämä tutkimus osoittaa, että kohdeyrityksen varaston tilausten käsittelyaikaa voidaan parantaa jopa usealla päivällä ja työntekijöiden ajankäyttöä voidaan tehostaa. Investoimalla varaston tietojärjestelmään saavutetaan seuraavat edut: reaaliaikainen varastopaikkojen saldotiedon ylläpito, nopeutunut keruuprosessi ja tilausten käsittely. Puutteet keruupaikoilla voidaan poistaa asettamalla järjestelmässä hälytysrajatoiminnallisuus käyttöön. Tuotteiden etsiminen poistuu, koska operaatiot suoritetaan kannettavan käsipäätteen avulla, joka ohjaa käyttäjää varastopaikkojen välillä. Analysoimalla järjestelmään karttuvaa dataa, voidaan myös tilan ahtautta poistaa, koska ottofrekvessin mukaan harvoin toimitettavat tuotteet voidaan siirtää pois varsinaisen varaston varastopaikoilta. Kohdeyrityksen varastorakennuksen hyötykorkeus on 7 metriä ja lavojen korkeudet vaihtelevat voimakkaasti. Tästä johtuen, investointi varastoautomaattiin tulee ottaa harkintaan tietojärjestelmäprojektin jälkeen. Varastoautomaatin edut ovat: varaston tehokas pinta-alan ja korkeuden käyttö, nopeutunut keruuprosessi ja keruuvirheiden vähentyminen

Family-based performance analysis of variant-rich software systems

We study models of software systems with variants that stem from a specific choice of configuration parameters with a direct impact on performance properties. Using UML activity diagrams with quantitative annotations, we model such systems as a product line. The efficiency of a product-based evaluation is typically low because each product must be analyzed in isolation, making difficult the re-use of computations across variants. Here, we propose a family-based approach based on symbolic computation. A numerical assessment on large activity diagrams shows that this approach can be up to three orders of magnitude faster than product-based analysis in large models, thus enabling computationally efficient explorations of large parameter spaces