Search

QC 20240326

QC 20240122

QC 20240122

QC 20240130

Developing software for complicated systems is often done by collaboration and consists of deliverables by a multitude of organisations. The deliverables can range from smaller devices and commercial-off-the-shelf software components, to larger systems. This is the situation during the development of the embedded system for large vehicles or machines. Many companies within the embedded industry are transitioning to using Service-Orientation to develop high-quality software and reduce costs. However, when integrating different external systems with an internal, service-oriented system there may arise difficulties since the communication patterns, i.e. interface, cannot be changed to fit the internal system. This study aims to develop a design solution that can be used to integrate different external systems with an internally developed service-oriented system in an entire software product line, including the handling of variability by parametrization. The solution is evaluated by software developers at a company in such a situation. To develop the design solution design science methodology is applied, which is an iterative process that continuously improves the candidate solution until satisfactory according to various stakeholders. The resultant design solution includes the use of wrappers-based interaction between systems, where so-called adapters are used when the internal system acts as a client to an external system, and using gateways for when the internal systems acts as a server to an external system. We also observe the need for a system integration view to describe the relations and available communication mechanisms between systems, i.e. the gateways and adapters. We conclude that to integrate a service-oriented software system with non-service-oriented systems, there can be benefits to using an abstraction layer between systems to protect the internally developed software architecture from being affected by the nature of the external system. Attempting to

QC 20240719

No ISSNQC 20240702

QC 20240702

QC 20240521

This study examines the notion of substitutionalism, which assumes that the introduction of sustainable alternatives will inherently displace unsustainable production and consumption systems. By studying the emergence of two historical examples of sustainable consumption, book and video rental, this study offers a unique opportunity to understand the effects of sharing from a distance and as a dominant consumption practice. The findings show that commercial lending did not displace new sales; instead, it transformed these subjects into mass-consumer products. Rental offered a lower price, greater supply, established new branches, and turned reading books and watching movies at home into consumer cultures. Producers initially resisted rental, but seized shares of the income as rental grew, and controlled the rental market so that cannibalization of the conventional consumption practices was avoided. This research challenges the core assumption of substitutionalism and highlights the need for a deeper understanding of market dynamics., QC 20240403

QC 20240614

QC 20240514

QC 20240403

QC 20240412

QC 20240412

Is circular economy a wonderful thing with no problems that can solve the climate crisis all by itself? Of course not. Can examining the problems with circular economy help us to better apply its principles and achieve better results?Yes. Dr Alison Stowell and colleagues Professor Hervé Corvellec and Dr Nils Johansson outline criticisms of the principle, and how they could help make the circular economy an actual solution to actual problems rather than a cure-all.

QC 20231122

QC 20221201

QC 20230901

QC 20230824

QC 20230807

QC 20230511

QC 20231122

Vätgas har en tendens att i läcka ut i små mängder i kopplingar samt även diffusera igenom de flesta material. Detta innebär, tillsammans med vätgasens utmanande förbränningsegenskaper, att normalventilation av utrymmen där vätgas hanteras är mycket viktig.I denna rapport presenteras kortfattat en ny metod för dimensionering av normalventilation baserad på multizon‐konceptet där utrymmet delas in i olika celler där flödet mellan dessa sedan beräknas.Metoden har fördelen gentemot CFD‐simuleringar att den är mycket snabbare och möjliggör därmedoptimering av ventilationsarean/‐flödet med rimliga simuleringstider.Modellen används i denna rapport för att undersöka hur parametrar kopplade till såväl utrymmet (längd, bredd och höjd), utsläppet (hålstorlek, lagringstryck och utsläppets höjd) som omgivningen (temperaturen) påverkar behovet av normalventilation – både för naturlig och mekanisk ventilation. Syftet är att studien ska utgöra ett underlag i en pågående revidering av MSB:s föreskrift ombrandfarliga gaser (MSBFS 2020:1) med avseende på vätgashantering.Slutsatsen var att utrymmets storlek (som är grunden för dagens krav) har ett förhållandevis svagt samband med behovet av ventilation där en fördubbling innebar ca 20% högre flöden och större area. Ett betydligt starkare samband finns med läckagets storlek och därför kan en koppling mellan erforderlig ventilationsarea (eller ventilationsflöde) och rördimensioner i utrymmet stämma bättre överens med de underliggande fysikaliska fenomenen.OBS! Modellen är fortfarande under pågående validering vilket gör att resultaten ska tolkas med viss försiktighet

Due to the small characteristic molecular size of hydrogen, small leaks are more common in hydrogen systems compared to similar systems with hydrocarbons. This, together with the high reactivity, makes an efficient ventilation system very important in hydrogen applications. There are several models available for ventilation sizing that are based on either a well-mixed assumption or a fully stratified situation. However, experiments show that many realistic releases will be neither, and therefore additional models are needed. One possibility is to use CFD-models, but the small release sizes for pinhole releases (<<1 mm) make it difficult to find an appropriate mesh without excessive computational time (especially since the simulations need to be iterated to find the optimum ventilation size). An alternative approach, which is described and benchmarked in the current paper, is to use a multi-zone model where the domain is divided into several large cells where the mass exchange is simplified compared to CFD, and thus simulation time is reduced. The flow in the model is governed by mass conservation and density differences, due to concentration gradients, using the Bernoulli equation. The release of gas generates a plume which is modelled based on an empirical plume model which gives the entrainment and hydrogen source term for each cell. The model has a short run time and will therefore allow optimization in a short time frame. The model is benchmarked against five experiments with helium at the Canadian Nuclear Laboratories (CNL) in Canada and one hydrogen experiment performed at Lodz University of Technology in Poland. The result shows that the model can reasonably well reproduce accumulation in the experiments with small release without ventilation, but appears to slightly underestimate the level of stratification and the interface height for ventilated cases where the source is elevated from the floor level.