A mapping study on documentation in Continuous Software Development

Context: With an increase in Agile, Lean, and DevOps software methodologies over the last years (collectively referred to as Continuous Software Development (CSD)), we have observed that documentation is often poor. Objective: This work aims at collecting studies on documentation challenges, documentation practices, and tools that can support documentation in CSD. Method: A systematic mapping study was conducted to identify and analyze research on documentation in CSD, covering publications between 2001 and 2019. Results: A total of 63 studies were selected. We found 40 studies related to documentation practices and challenges, and 23 studies related to tools used in CSD. The challenges include: informal documentation is hard to understand, documentation is considered as waste, productivity is measured by working software only, documentation is out-of-sync with the software and there is a short-term focus. The practices include: non-written and informal communication, the usage of development artifacts for documentation, and the use of architecture frameworks. We also made an inventory of numerous tools that can be used for documentation purposes in CSD. Overall, we recommend the usage of executable documentation, modern tools and technologies to retrieve information and transform it into documentation, and the practice of minimal documentation upfront combined with detailed design for knowledge transfer afterwards. Conclusion: It is of paramount importance to increase the quantity and quality of documentation in CSD. While this remains challenging, practitioners will benefit from applying the identified practices and tools in order to mitigate the stated challenges

Thinking with data visualisations: cognitive processing and spatial inferences when communicating climate change

Data visualisations can be effective for communicating scientific data, but only if they are understood. Such visualisations (i.e. scientific figures) are used within assessment reports produced by the Intergovernmental Panel on Climate Change (IPCC). However, IPCC figures have been criticised for being inaccessible to non-experts. This thesis presents a thematic analysis of interviews with IPCC authors, finding that a requirement to uphold scientific accuracy results in complex figures that are difficult for non-experts to comprehend, and which therefore require expert explanation. Evidence is subsequently presented showing that figures with greater visual complexity are associated with greater perceived comprehension difficulty among non-experts. Comprehension of complex data visualisations may require readers to make spatial inferences. When interpreting a time-series graph of climate data, it was found that non-experts did not always readily identify the long-term trend. Two experiments then show that linguistic information in the form of warnings can support spatial representations for trends in memory by directing visual attention during encoding (measured using eyetracking). This thesis also considers spatial inferences when forming expectations about future data, finding that expectations were sensitive to patterns in past data. Further, features that act on bottom-up perceptual processes were largely ineffective in supporting spatial inferences. Conversely, replacing spatial inferences by explicitly representing information moderated future expectations. However, replacing spatial inferences might not always be desirable in real-world contexts. The evidence indicates that when information is not explicitly represented in a data visualisation, providing top-down knowledge may be more effective in supporting spatial inferences than providing visual cues acting on bottom-up perceptual processes. This thesis further provides evidence-based guidelines drawn from the cognitive and psychological sciences to support climate change researchers in enhancing the ease of comprehension of their data visualisations, and so enable future IPCC outputs to be more accessible

Sorting the Healthy Diet Signal from the Social Media Expert Noise: Preliminary Evidence from the Healthy Diet Discourse on Twitter

: Over 2.8 million people die each year from being overweight or obese, a largely preventable disease. Social media has fundamentally changed the way we communicate, collaborate, consume, and create content. The ease with which content can be shared has resulted in a rapid increase in the number of individuals or organisations that seek to influence opinion and the volume of content that they generate. The nutrition and diet domain is not immune to this phenomenon. Unfortunately, from a public health perspective, many of these ‘influencers’ may be poorly qualified in order to provide nutritional or dietary guidance, and advice given may be without accepted scientific evidence and contrary to public health policy. In this preliminary study, we analyse the ‘healthy diet’ discourse on Twitter. While using a multi-component analytical approach, we analyse more than 1.2 million English language tweets over a 16-month period in order to identify and characterise the influential actors and discover topics of interest in the discourse. Our analysis suggests that the discourse is dominated by non-health professionals. There is widespread use of bots that pollute the discourse and seek to create a false equivalence on the efficacy of a particular nutritional strategy or diet. Topic modelling suggests a significant focus on diet, nutrition, exercise, weight, disease, and quality of life. Public health policy makers and professional nutritionists need to consider what interventions can be taken in order to counteract the influence of non-professional and bad actors on social media

Mass introduction of electric passenger vehicles in Brazil: impact assessment on energy use, climate mitigation and on charging infrastructure needs for several case studies

Mobility has proved to be a major challenge for human development, especially in urban centers worldwide, where more displacement is required, since fossil fuels consumption is increasing as well as greenhouse gas (GHG) emissions, causing air quality degradation and global warming. The predicted population increase in cities tends to increase the demand for mobility and to further exacerbate those impacts. Therefore, sustainable transport is key for the future of mobility, and electric vehicle (EV) has emerged as a recognized sustainable option. However, there are many electric vehicle barriers diffusion. This research aims to contribute to the diffusion of EV in Brazil, by assessing: 1) whether EV is a more sustainable technology when compared with ethanol vehicle; 2) the impacts of the expansion of electric mobility on CO2 emissions, in Sao Paulo; 3) how to overcome the barriers for the charging infrastructure deployment at the municipality level, in Sao Paulo, Rio de Janeiro and Belo Horizonte; and 4) key challenges and opportunities from the mass adoption of EV in Brazil. A plethora of different methods were used, including scenario analysis, multi-criteria decision methods, geographic information systems and SWOT analysis. Main results point to EV as the best technology to mitigate passenger transport related CO2 emissions in Brazil, due to its low carbon footprint. In Sao Paulo, this option could reduce around 11 MtCO2 by 2030 and save 6,200 billion USD in energy with the replacement of 20 percent of gasoline cars with EV. To meet 1 percent of EV's market share, Sao Paulo, Rio de Janeiro and Belo Horizonte together will need around 6,500 charging stations concentrated in around 1/3 of their territories (level 2). Brazil may likely have up to 10 percent of EV penetration by 2030, with the diffusion taking place mostly in southeastern municipality. Ethanol, lack of electric mobility public policy, non-urbanized like subnormal agglomerates, and risk areas, like flood hazard, are major obstacles for EV diffusion in Brazil

Hurricane Harvey Report:A Fact-Finding Effort in the Direct Aftermath of Hurricane Harvey in the Greater Houston Region

On August 25, 2017, Hurricane Harvey made landfall near Rockport, Texas as a Category 4 hurricane with maximum sustained winds of approximately 200 km/hour. Harvey caused severe damages in coastal Texas due to extreme winds and storm surge, but will go down in history for record-setting rainfall totals and flood-related damages. Across large portions of southeast Texas, rainfall totals during the six-day period between August 25 and 31, 2017 were amongst the highest ever recorded, causing flooding at an unprecedented scale. More than 100,000 residential properties are estimated to have been affected in southeast Texas. It is likely that Harvey will rank among the costliest storms in U.S. history. In the wake of Hurricane Harvey, Delft University of Technology has initiated a Harvey Research Team to undertake a coordinated multidisciplinary investigation of the events with a focus on the greater Houston area. This ‘fact-finding’ research is based on information available from public sources during and in the first weeks after the event. Results are therefore preliminary, but aim to provide insight into lessons that can be learned for both Texas and the Netherlands. As part of the investigations, a hackathon with more than 80 participants was organized to collect and analyze available public information. Houston was especially hard hit by flooding. During the event, all 22 watersheds in the greater Houston area experienced flooding. Many of Houston’s creeks and bayous exceeded their channel capacities, reaching water levels never before recorded. Across large portions of Harris County, rainfall totals exceeded the 1000-year return period. In addition, the water from the two reservoirs protecting downtown Houston (Addicks and Barker) were opened on August 28 to prevent catastrophic damages to the dams and further flooding in upstream communities. The releases exacerbated flooding in the areas downstream of the dams and an estimated 4,000 homes in neighborhoods downstream of the dams were impacted by flooding. The consequences of the event in the greater Houston area have been characterized in terms of economic damages, loss of life and impacts on critical infrastructure, airports and industry. In total, more than 100,000 homes were affected more than 70 fatalities were reported in the greater Houston area. The event highlighted the vulnerability of industrial facilities, as several cascading impacts (releases of toxic materials and explosions) were reported. Emergency response has been assessed. No large-scale mandatory evacuation was ordered before or during Harvey. However, it appeared that several local evacuations were ordered for areas with specific risks and circumstances. During the event, many people were trapped by rising waters necessitating a major rescue operation. In total, more than 10,000 rescues were made by professional and volunteer rescuers. Social media played an important role during the event and recovery, as an additional source of information, to inform emergency managers and as a means to organize community response e.g. for clean-up. Also, messages were conveyed through social media, e.g. a report of a levee breach that appeared to be incorrect afterwards. Major flooding is a problem that has multiple causes from both physical and social origin. Based on the investigations, recommendations for future research and lessons for flood management have been formulated. A better understanding of the issues studied in this report is expected to contribute to a knowledge basis for further in-depth investigations and future directions for flood risk reduction. Data collection and Report production funded by DIMI and DSys Special Case 'Houston Galveston Bay Region, Texas, USA' Project 'Harvey hackathon' and follow-up researc

Electric autonomous tractors in Swedish agriculture : A systems analysis of economic, environmental and performance effects

Use of battery-electric vehicles has become common in different sectors, as a measure to reduce greenhouse gas emissions. Driveline electrification in agricultural machinery could reduce emissions and increase driveline efficiency, but implementation has been hindered by the low energy-carrying capacity of batteries compared with conventional fuels. Combining battery-electric drivelines and autonomous operation would provide important synergies by mitigating or eliminating many of negative aspects of electrification, while retaining the benefits from both systems.This thesis evaluated the potential and analysed the intricate workings of a battery-based autonomous electric vehicle system by applying systems analysis, economic analysis and life cycle assessment, through simulations and modelling. The vehicle system was evaluated on a theoretical Swedish grain farm of 200 ha using a conventional cropping system. Soil compaction, battery ageing, queueing dynamics, field trafficability, energy storage and weather effects were all included in simulations. This allowed comparison of performance, cost and environmental impacts for a conventional fieldwork tractor and a system with several smaller autonomous battery-electric tractors.The evaluation showed that the autonomous electric tractors were able to match or exceed the daily work rate of the conventional tractor, while reducing energy use (by 47-75%), lowering annual costs (by 32-37%) and reducing soil compaction. The environmental impact was generally also lower, with up to a 74% reduction in greenhouse gas emissions over the system’s life cycle. These results indicate great potential for autonomous electric tractors in future agricultural fieldwork, as combining the electric driveline and autonomous technologies allowed the benefits from both to be used to greater effect than either by itself

PV Charging and Storage for Electric Vehicles

Electric vehicles are only ‘green’ as long as the source of electricity is ‘green’ as well. At the same time, renewable power production suffers from diurnal and seasonal variations, creating the need for energy storage technology. Moreover, overloading and voltage problems are expected in the distributed network due to the high penetration of distributed generation and increased power demand from the charging of electric vehicles. The energy and mobility transition hence calls for novel technological innovations in the field of sustainable electric mobility powered from renewable energy. This Special Issue focuses on recent advances in technology for PV charging and storage for electric vehicles

State of the Art and Future Perspectives in Smart and Sustainable Urban Development

This book contributes to the conceptual and practical knowledge pools in order to improve the research and practice on smart and sustainable urban development by presenting an informed understanding of the subject to scholars, policymakers, and practitioners. This book presents contributions—in the form of research articles, literature reviews, case reports, and short communications—offering insights into the smart and sustainable urban development by conducting in-depth conceptual debates, detailed case study descriptions, thorough empirical investigations, systematic literature reviews, or forecasting analyses. This way, the book forms a repository of relevant information, material, and knowledge to support research, policymaking, practice, and the transferability of experiences to address urbanization and other planetary challenges