Communication Centric Design in Complex Automotive Embedded Systems

Automotive embedded applications like the engine management system are composed of multiple functional components that are tightly coupled via numerous communication dependencies and intensive data sharing, while also having real-time requirements. In order to cope with complexity, especially in multi-core settings, various communication mechanisms are used to ensure data consistency and temporal determinism along functional cause-effect chains. However, existing timing analysis methods generally only support very basic communication models that need to be extended to handle the analysis of industry grade problems which involve more complex communication semantics. In this work, we give an overview of communication semantics used in the automotive industry and the different constraints to be considered in the design process. We also propose a method for model transformation to increase the expressiveness of current timing analysis methods enabling them to work with more complex communication semantics. We demonstrate this transformation approach for concrete implementations of two communication semantics, namely, implicit and LET communication. We discuss the impact on end-to-end latencies and communication overheads based on a full blown engine management system

Supply chain and logistics in digital transformation

The aspirations to reduce environmental impact, the ongoing labor shortages, and the expanding possibilities of digital technologies urge logistics companies to reinvent their network designs, their methods of operating, and even their business models. For the logistics sector, we provide an overview of contextual perspectives, mechanisms of change, and outcomes in digitization, digitalization, and digital transformation. Specifically, we evaluate developments and opportunities in the logistics sector from the viewpoint of food distribution in cities. We find that both customers and suppliers in the food supply chain are willing to initiate or join novel logistics concepts that require collaboration with other stakeholders in the supply chain. Notably, we investigate attitudes towards the concept of bundling, where goods of different suppliers are jointly delivered to customers by the same vehicle. Furthermore, we quantitatively demonstrate the added value of such collaborative efforts. Collaborations between companies require an increased effort in digital exchange of data and other digital technologies to reap the potential benefits we determined. We identify an impending transformation in the business model of innovative food distributors that may change the landscape of food distribution in cities

Digital transformation in logistics from the perspective of a food distributor

The aspirations to reduce environmental impact, the ongoing labor shortages, and the expanding possibilities of digital technologies urge logistics companies to reinvent their network designs, their methods of operating, and even their business models. For the logistics sector, we provide an overview of contextual perspectives, mechanisms of change, and outcomes in digitization, digitalization, and digital transformation. Specifically, we evaluate developments and opportunities in the logistics sector from the viewpoint of food distribution in cities. We find that both customers and suppliers in the food supply chain are willing to initiate or join novel logistics concepts that require collaboration with other stakeholders in the supply chain. Notably, we investigate attitudes towards the concept of bundling, where goods of different suppliers are jointly delivered to customers by the same vehicle. Furthermore, we quantitatively demonstrate the added value of such collaborative efforts. Collaborations between companies require an increased effort in digital exchange of data and other digital technologies to reap the potential benefits we determined. We identify an impending transformation in the business model of innovative food distributors that may change the landscape of food distribution in cities

Reliability prediction in model driven development

Evaluating the implications of an architecture design early in the software development lifecycle is important in order to reduce costs of development. Reliability is an important concern with regard to the correct delivery of software system service. Recently, the UML Profile for Modeling Quality of Service has defined a set of UML extensions to represent dependability concerns (including reliability) and other non-functional requirements in early stages of the software development lifecycle. Our research has shown that these extensions are not comprehensive enough to support reliability analysis for model-driven software engineering, because the description of reliability characteristics in this profile lacks support for certain dynamic aspects that are essential in modeling reliability. In this work, we define a profile for reliability analysis by extending the UML 2.0 specification to support reliability prediction based on scenario specifications. A UML model specified using the profile is translated to a labelled transition system (LTS), which is used for automated reliability prediction and identification of implied scenarios; the results of this analysis are then fed back to the UML model. The result is a comprehensive framework for addressing software reliability modeling, including analysis and evolution of reliability predictions. We exemplify our approach using the Boiler System used in previous work and demonstrate how reliability analysis results can be integrated into UML models

Welding of thin sheet steels in marine applications

Many metal structures are assembled from thin plate with welded supports for stiffness to resist local loadings. However, welded joints, which require large heat input, may incur significant distortion in the finished plate. Although the causes of distortion are known, and have been the focus of number of studies, there is still a lack of fundamental understanding of process and physical parameters in causing distortion. The overall aim of this work is to identify the interaction of process and physical parameters in causing distortion of welded ferritic thin steel plates. Experimental measurements and the finite element method are used to identify the relationship between distortion and the influence of pre-existing (residual) stresses in the plates. Effect of onset of transformation temperature on distortion is examined. An improved comprehension of the mechanisms causing distortion, and a readily useable model to explore alternatives has significant potential in wide range of industries and thus is a major driving force for continued research. The ability to predict with reasonable certainty the geometry of distortion will enable users to evaluate alternative design and production parameters. The work is divided into eight chapters: The first chapter gives an introduction and lists the objectives of the research. A theoretical exploration of the problem in addition to a survey of relevant work with regard to the welding of ferritic steels, weld microstructures, residual stresses, finite element modelling (FEM) and an overview of experimental techniques including transmission electron microscopy (TEM), scanning electron microscopy (SEM), electron backscattered diffraction (EBSD), neutron diffraction (ND) is given in chapter 2. In chapter 3 experimental investigation results including both post-weld and in-situ microstructure observation and residual stress distribution are presented and discussed [1, 2]. To provide a qualitative insight into fundamental understanding of development of residual stress, a finite element model that considers both the thermal and the transformation strains caused by solid-state phase transformation was developed and is presented in the chapter 4 [3]. A validated finite element model for computation of residual stresses is presented in the chapter 5 [4]. Special emphasis was placed on the effect of transformation temperature on residual stress development in both the actual weld and the model. Most of the modelling results were validated against experimental measurements. Chapter 6 presents a sensitivity study on the effect of parameter changes on distortion. An attempt was made to elucidate both the effect of transformation start temperature and the initial distortion on the final distortion [5]. Chapter 7 details application of a model for variant selection [6], which is based on work published in [7, 8] to actual welds. This work was performed to elucidate the effect of texture on residual stress. Finally the last chapter draws together the major conclusions of the thesis, and suggests future avenues of investigation to progress the research discussed here

Home Energy Efficiency and Mortgage Risks: Research funded by the Institute for Market Transformation

Many have theorized that energy efficient homes should have lower default risks than standard homes because the former are associated with lower energy costs, which leaves more money to make the mortgage payment. However, few empirical studies have been conducted due to limited data availability. This study examines actual loan performance data obtained from CoreLogic, the lending industry's leading source of such data. To assess whether residential energy efficiency is associated with lower default and prepayment risks, a national sample of about 71,000 ENERGY STAR- and non-ENERGY STAR-rated single-family home mortgages was carefully constructed, accounting for loan, household, and neighborhood characteristics.The study finds that default risks are on average 32 percent lower in energy-efficient homes, controlling for other loan determinants. This finding is robust, significant, and consistent across several model specifications. A borrower in an ENERGY STAR residence is also one-quarter less likely to prepay the mortgage. Within ENERGY STAR-rated homes, default risk is lower for more energy-efficient homes. The lower risks associated with energy efficiency should be taken into consideration when underwriting mortgages