Abstract Although “feature” is a common term across requirements engineering, product-line engineering, and agile methods, its operationalization in practice–especially through feature branches–has received little empirical attention. Feature branches are widely recommended on platforms like GitHub; yet, empirical evidence on how they are actually used is scarce. This study investigates feature-branch development practices in open-source software (OSS) projects. We conducted a large-scale empirical analysis of 27,103 feature branches from 3,388 popular GitHub repositories. Using branch-naming conventions, we identified feature branches and measured their lifespan, commit history, and commit-share distributions among contributors. In addition, we profiled contributors according to their opened issues, opened pull requests, number of followers, and total stars. Our analysis revealed that feature branches in open-source projects are long-lived, with a median lifespan exceeding two years, diverging from the short, agile iterations typically employed in software development. Commit intensity is low and irregular, averaging fewer than two commits per day. Contribution is highly unequal within feature branches: a small share of contributors accounts for most commits, revealing strong dependence on a small subset of developers. These findings have several practical implications. Our findings suggest that monitoring contribution concentration within feature branches– for instance, by computing the share of commits attributable to the top contributor or a Gini coefficient over the branch’s commit history–can help maintainers identify branches where development knowledge is held by very few individuals. Likewise, rolling commit intensity–computable directly from commit timestamps–may serve as an early signal of branch stagnation in OSS projects. Moreover, these findings establish an empirical baseline for future studies, including analyses of proprietary repositories.

Sustainability is gaining increasing importance in software engineering education, as future software engineers must understand the environmental and societal effects of the systems they create. To prepare students for these challenges, it is essential to integrate sustainability into practical courses where students can explore its principles and real-world implications. However, there are still limited examples of how sustainability can be effectively embedded into existing university curricula, highlighting a significant gap in educational practice. In this paper, we describe an experience report of a practical and agile-oriented undergraduate software engineering course that integrates sustainability. We found that the students were successful in identifying various effects of a software system on different sustainability dimensions. Furthermore, sustainability aspects can be seamlessly integrated into existing courses with minimal effort. Therefore, we share our learning materials with the hope that they will inspire and be reused by other software engineering educators.

To foster a sustainable society within a sustainable environment, we must dramatically reshape our work and consumption activities, most of which are facilitated through software. Yet, most software engineers hardly consider the effects on the sustainability of the IT products and services they deliver. This issue is exacerbated by a lack of methods and tools for this purpose. Despite the practical need for methods and tools that explicitly support consideration of the effects that IT products and services have on the sustainability of their intended environments, such methods and tools remain largely unavailable. Thus, urgent research is needed to understand how to design such tools for the IT community properly. In this article, we describe our experience using design science to create the Sustainability Awareness Framework (SusAF), which supports software engineers in anticipating and mitigating the potential sustainability effects during system development. More specifically, we identify and present the challenges faced during this process. The challenges that we have faced and addressed in the development of the SusAF are likely to be relevant to others who aim to create methods and tools to integrate sustainability analysis into their IT products and services development. Thus, the lessons learned in SusAF development are shared for the benefit of researchers and other professionals who design tools for that end.

Sustainability has become a widely discussed topic in software and requirements engineering. However, in the context of agile software development processes, little is known about how to identify potential sustainability effects of software systems. The goal of our research is to investigate how requirements engineering knowledge on sustainability can be incorporated into agile frameworks like Scrum. In this experience paper, we present the results of two case studies from ongoing agile development projects where the Sustainability Awareness Framework was applied. Within workshops, more than 20 potential sustainability effects have been identified for each of the systems based on their product visions. Furthermore, we analyzed the product backlogs and found that more than half of the backlog items of both systems can be related to at least one of the identified sustainability effects. This suggests that a sustainability analysis of backlog items can support the early identification of potential sustainability effects in Scrum. Our findings suggest that the Sustainability Awareness Framework can be successfully used by practitioners in agile settings based on the guidelines provided by the Sustainability Awareness Framework.

Sustainability is becoming increasingly important in software engineering, especially in requirements engineering. Several requirements engineering approaches have already been proposed to deal with the question of how impacts of requirements on sustainability dimensions can be identified and managed. However, in contrast to requirements engineering, little is known about how to identify the potential sustainability effects of software systems in agile software development and how to foster the agile development of sustainable software. The goal of our research is to investigate how sustainability can be incorporated into Scrum. Our ongoing work targets the development of a Sustainability-Aware Scrum Framework that integrates requirements engineering knowledge into Scrum to raise awareness around the sustainability impacts of software systems and to make software systems more sustainable. The main contribution of our work is a set of recommendations on how the Scrum framework, as the major agile development process, can be extended towards sustainability. Furthermore, we discuss an evaluation plan, present a prototype of a software tool that supports tracking possible sustainability impacts of user stories, and provide preliminary results.

Abstract Various approaches toward the development of sustainable software systems have been proposed by the requirements engineering community over the last decade. We conducted a systematic mapping study, analyzed 55 publications, and identified 29 approaches that have been published since the year 2000. We analyzed how the approaches evolved over time and how the publications and authors are influenced by each other. Furthermore, the approaches are analyzed in terms of their supported requirements engineering activities, along with the evidence provided in the publications. Additionally, we also analyzed which sustainability definitions have been used, if an iterative application of the approaches is discussed, and if the approaches also provide a tool-support for practitioners. We noticed an increase of publications on requirements engineering approaches toward sustainability in the last years, whereas a majority discuss sustainability based on the same multi-dimensional concept. Although different case studies have been already conducted, we noticed a lack of an industrial application. Our main findings concern the need of an evaluation on how the proposed requirements engineering approaches can also be applied in agile software development processes. Additionally, we also promote the development of supporting software tools to support practitioners in adapting the proposed approaches.

The Sustainable Development Goals (SDGs) of the United Nations focus on key issues for the transformation of our world towards sustainability. We argue for stronger integration of the SDGs into requirements and software engineering and for the creation of methods and tools that support the analysis of potential effects of software systems on sustainability in general and on SDGs in particular. To demonstrate one way of undertaking this integration, we report on how the Sustainability Awareness Framework (SusAF -- a tool developed by the authors of this paper) can be mapped to the SDGs, allowing the identification of potential effects of software systems on sustainability and on the SDGs. This mapping exercise demonstrates that it is possible for requirements engineers working on a specific system to consider that system's impact with respect to SDGs.

Context. The use of standards is considered a vital part of any engineering discipline. So one could expect that standards play an important role in Requirements Engineering (RE) as well. However, little is known about the actual knowledge and use of RE-related standards in industry.Objective. In this article, we investigate to which extent standards and related artifacts such as templates or guidelines are known and used by RE practitioners.Method. To this end, we have conducted a questionnaire-based online survey. We could analyze the replies from 90 RE practitioners using a combination of closed and open-text questions.Results. Our results indicate that the knowledge and use of standards and related artifacts in RE is less widespread than one might expect from an engineering perspective. For example, about 47% of the respondents working as requirements engineers or business analysts do not know the core standard in RE, ISO/IEC/IEEE 29148. Participants in our study mostly use standards by personal decision rather than being imposed by their respective company, customer, or regulator. Beyond insufficient knowledge, we also found cultural and organizational factors impeding the widespread adoption of standards in RE.Conclusions. Overall, our results provide empirically informed insights into the actual use of standards and related artifacts in RE practice and – indirectly – about the value that the current standards create for RE practitioners.

Mining app stores and social media has proven to be a good source for collecting user feedback to foster requirements engineering and software evolution. Recent literature on mining software-related data from social platforms, such as Twitter and Facebook, shows that it complements app store mining. However, there are many other platforms where users discuss and provide feedback on software applications that are not thoroughly researched and analysed. One of such platforms is reddit. In this paper, we introduce reddit as a new potential data source and explore if and how requirements engineering and software evolution can benefit from obtaining user feedback from reddit. We also present an exploratory study in which we analysed the usage characteristics (i.e., frequency of posts, number of comments, and number of users for each subreddit) of reddit posts about software applications. Furthermore, we examined the content of the posts and the results reveal that almost 54% of posts contain useful information. Finally, we investigated the potential of automatic classification and applied machine learning algorithms to unstructured and noisy reddit data to perform automated classification into the categories of bug reports, feature related, and irrelevant. We found that the Support Vector Machine algorithm with the F1-score of 84% can be effective in categorizing reddit posts. Our results show that reddit posts provide useful feedback on software applications that can foster requirements engineering and software evolution.

Integrating novel software systems in our society, economy, and environment can have far-reaching effects. As a result, software systems should be designed in such a way as to maintain or improve the sustainability of the socio-technical system of their destination. However, a paradigm shift is required to raise awareness of software professionals on the potential sustainability effects of software systems. While Requirements Engineering is considered the key to driving this change, requirements engineers lack the knowledge, experience and methodological support for doing so. This paper presents a question-based framework for raising awareness of the potential effects of software systems on sustainability, as the first step towards enabling the required paradigm shift. A feasibility study of the framework was carried out with two groups of computer science students. The results of the study indicate that the framework helps enable discussions about potential effects that software systems could have on sustainability.

User feedback and usage data are a valuable source of knowledge for requirements engineering (RE) and software evolution. Recent research in RE has focused on the acquisition and analysis of such user input. However, we argue that important information complementing existing data has been neglected, namely users' emotions shown during app usage, which provide insight into how users experience the app. We are aware that tracking users' emotions at large-scale might be challenging. So far, emotion tracking is often applied in lab and test settings only. We envision an unobtrusive emotion tracker running on the users' smartphones in their regular usage context. However, we do not know whether such an approach would be accepted by the app users and which requirements such an emotion-tracking solution would need to fulfill. In this paper, we present the first results from our exploratory interview study with eight mobile app users regarding their preferences and concerns with respect to emotion tracking. Early results are encouraging and suggest that app users tend to accept emotion tracking during app usage, having only minor privacy concerns. In this paper, we discuss our ongoing research, including the long-term direction and prospects of considering users' emotions for RE.

Context: Software evolution ensures that software systems in use stay up to date and provide value for end-users. However, it is challenging for requirements engineers to continuously elicit needs for systems used by heterogeneous end-users who are out of organisational reach. Objective: We aim at supporting continuous requirements elicitation by combining user feedback and usage monitoring. Online feedback mechanisms enable end-users to remotely communicate problems, experiences, and opinions, while monitoring provides valuable information about runtime events. It is argued that bringing both information sources together can help requirements engineers to understand end-user needs better. Method/Tool: We present FAME, a framework for the combined and simultaneous collection of feedback and monitoring data in web and mobile contexts to support continuous requirements elicitation. In addition to a detailed discussion of our technical solution, we present the first evidence that FAME can be successfully introduced in real-world contexts. Therefore, we deployed FAME in a web application of a German small and medium-sized enterprise (SME) to collect user feedback and usage data. Results/Conclusion: Our results suggest that FAME not only can be successfully used in industrial environments but that bringing feedback and monitoring data together helps the SME to improve their understanding of end-user needs, ultimately supporting continuous requirements elicitation.

Requirements Engineering (RE) plays a critical role in software system development and is argued to be the key leverage point for practitioners who want to design sustainable software-intensive systems. However, existing RE methods and tools do not explicitly facilitate the discussion and negotiation of sustainability-related concerns. This leads to insufficient or onedimensional perceptions of sustainability. In this paper, we discuss our understanding of sustainability and its relationship with requirements. Based on the outcomes of this discussion, we have extended the WinWin Negotiation Model by incorporating sustainability concepts so that the negotiation also includes the ability to consider the impact of requirements on sustainability. Applying this negotiation method in an exploratory industrial case study, we have learned that this approach stimulates the discussion on sustainability and its multiple dimensions. It also allows practitioners to reflect on requirements and their effects on sustainability. However, we have also observed that further in-depth requirements analysis is needed to analyse the long-term effects of requirements regarding sustainability.

Continuous requirements elicitation is an essential aspect of software product evolution to keep systems aligned with changing user needs. However, current requirements engineering approaches do not explicitly address sustainability in the evolution of systems. Reasons include a lack of awareness and a lack of shared understanding of the concept of sustainability in the RE community. Identifying and analysing the effects of requirements regarding sustainability is challenging, as these effects can have an impact on multiple stakeholders and manifest themselves in one or more sustainability dimensions at different points in time. We argue that crowd-focused semi-automated requirements engineering allows the engagement of a large number of stakeholders (including users and domain experts) in a continuous cycle of negotiation regarding the potential effects of requirements on sustainability. Based on a motivating scenario, we introduce the idea of a platform for crowd-focused requirements engineering that supports the evolution towards sustainability. For the three key aspects of this platform, we present our ongoing work and discuss early results. We outline how the platform can be utilised to improve the broader awareness and understanding of sustainability, not only for the involved crowd but also for researchers and society in general.

Enterprise Resource Planning (ERP) system vendors need to customize their products according to the domain-specific requirements of their customers. Systematic reuse of features and related ERP product customizations would improve software quality and save implementation time. In our previous research, we have developed a tool-based approach supporting feature-based reuse of ERP product customizations. Our tool environment automatically infers reusable features from requirements and their associated implementation artifacts. Furthermore, it allows domain experts to search for features based on natural language requirement descriptions representing the needs of new customers. Matching features can be automatically deployed to a new ERP product. In this paper, we present an industrial evaluation of our tool-based approach conducted together with an Austrian small- to medium-sized enterprise. A domain expert used our approach to identify matching features for 20 randomly selected requirements for new customer products and identified matching features for 17 of the 20 requirements. We compared the time needed to identify and deploy the candidate features with the time required to implement the requirements from scratch. We found that, in total, over 60% implementation time can be saved by applying our reuse approach presented in this case study.

Feedback communication channels allow end-users to express their needs, which can be considered in software development and evolution. Although feedback gathering and analysis have been identified as an important topic and several researchers have started their investigation, information is scarce on how software companies currently elicit end-user feedback. In this study, we explore the experiences of software companies with respect to feedback gathering. The results of a case study and online survey indicate two sides of the same coin: on the one hand, most software companies are aware of the relevance of end-user feedback for software evolution and provide feedback channels, which allow end-users to communicate their needs and problems. On the other hand, the quantity and quality of the feedback received varies. We conclude that software companies still do not fully exploit the potential of end-user feedback for software development and evolution.

Users of the Twitter microblogging platform share a vast amount of information about various topics through short messages on a daily basis. Some of these so called tweets include information that is relevant for software companies and could, for example, help requirements engineers to identify user needs. Therefore, tweets have the potential to aid in the continuous evolution of software applications. Despite the existence of such relevant tweets, little is known about their number and content. In this paper we report on the results of an exploratory study in which we analyzed the usage characteristics, content and automatic classification potential of tweets about software applications by using descriptive statistics, content analysis and machine learning techniques. Although the manual search of relevant information within the vast stream of tweets can be compared to looking for a needle in a haystack, our analysis shows that tweets provide a valuable input for software companies. Furthermore, our results demonstrate that machine learning techniques have the capacity to identify and harvest relevant information automatically.

Sustainability has emerged as a broad concern for society. Many engineering disciplines have been grappling with challenges in how we sustain technical, social and ecological systems. In the software engineering community, for example, maintainability has been a concern for a long time. But too often, these issues are treated in isolation from one another. Misperceptions among practitioners and research communities persist, rooted in a lack of coherent understanding of sustainability, and how it relates to software systems research and practice. This article presents a cross-disciplinary initiative to create a common ground and a point of reference for the global community of research and practice in software and sustainability, to be used for effectively communicating key issues, goals, values and principles of sustainability design for software-intensive systems.The centrepiece of this effort is the Karlskrona Manifesto for Sustainability Design, a vehicle for a much needed conversation about sustainability within and beyond the software community, and an articulation of the fundamental principles underpinning design choices that affect sustainability. We describe the motivation for developing this manifesto, including some considerations of the genre of the manifesto as well as the dynamics of its creation. We illustrate the collaborative reflective writing process and present the current edition of the manifesto itself. We assess immediate implications and applications of the articulated principles, compare these to current practice, and suggest future steps.

When software engineers collaborate, they frequently use whiteboards or paper for sketching diagrams. This is fast and flexible, but the resulting diagrams cannot be interpreted by software modeling tools. We present FLEXISKETCH TEAM, a tool solution consisting of a significantly extended version of our previous, single-user FLEXISKETCH tool for Android devices and a new desktop tool. Our solution for collaborative, model-based sketching of free-form diagrams allows users to define and re-use diagramming notations on the fly. Several users can work simultaneously on the same model sketch with multiple tablets. The desktop tool provides a shared view of the drawing canvas which can be projected onto an electronic whiteboard. Preliminary results from an exploratory study show that our tool motivates meeting participants to actively take part in sketching as well as defining ad-hoc notations.

Whiteboards and paper allow for any kind of notations and are easy to use. Requirements engineers love to use them in creative requirements elicitation and design sessions. However, the resulting diagram sketches cannot be interpreted by software modeling tools. We have developed FlexiSketch as an alternative to whiteboards in previous work. It is a mobile tool for model-based sketching of free-form diagrams that allows the definition and re-use of diagramming notations on the fly. The latest version of the tool, called FlexiSketch Team, supports collaboration with multiple tablets and an electronic whiteboard, such that several users can work simultaneously on the same model sketch. In this paper we present an exploratory study about how novice and experienced engineers sketch and define ad-hoc notations collaboratively in early requirements elicitation sessions when supported by our tool. Results show that participants incrementally build notations by defining language constructs the first time they use them. Participants considered the option to re-use defined constructs to be a big motivational factor for providing type definitions. They found our approach useful for longer sketching sessions and situations where sketches are re-used later on.

Requirements engineering (RE) is widely recognized as a crucial factor for the success of software projects. Therefore, companies often request assessments of RE processes and resulting artifacts to identify issues and improvement potential. However, industry claims that current assessment approaches do not always fulfill their needs regarding efficiency and effectiveness. Motivated by needs of both, companies asking for an assessment, and a company in the role of an assessor, we have developed a lightweight, tool-supported RE assessment approach. Apart from presenting the approach, we also discuss early experiences we gained from applying our assessment approach in real-world industrial projects.

Systematic variability management is an important prerequisite for successful software reuse. However, it requires significant effort and extensive domain knowledge to document and maintain information on variability. In this paper we present a tool-supported approach which supports semi-automatically inferring variability information from customized standard software products. The approach does not only enable the identification and documentation of variability information based on existing products, it is also capable of incrementally updating this information. To guarantee quick access to reusable code artifacts (e.g. requirements, features or software components), the presented solution stores these artifacts together with related requirements and a generated variability model in an asset repository. The tool-supported approach has been applied to customizations of Microsoft Dynamics AX ERP systems. Our experiences highlight the potential and benefits of our approach compared to manually gathering information on software variability.

The significant wide impact of mobile technologies (e.g., smartphones, tablets) and the difficulty of mastering their complexity (due to factors like constant emergence and evolution) pose new challenges to many (if not all) software engineering disciplines. We particularly see these challenges when thinking of average citizens that carry out their daily activities in smart environments where mobile technologies and sensors installed provide many potential advantages to support them. Applications that could enable informed decision-making are currently beyond what software developers can provide. This position paper discusses challenges, and highlights current approaches available in order to support decision-making for thoughtful living. We present an initial version of a comprehensive framework to overcome the challenges identified and analyse which software engineering research lines may help to implement it. A motivating scenario is used to conduct the discussion.

Traditionally, metamodeling is an upfront activity performed by experts for defining modeling languages. Modeling tools then typically restrict modelers to using only constructs defined in the metamodel. This is inappropriate when users want to sketch graphical models without any restrictions and only later assign meanings to the sketched elements. Upfront metamodeling also complicates the creation of domain-specific languages, as it requires experts with both domain and metamodeling expertise. In this paper we present a new approach that supports modelers in creating metamodels for diagrams they have sketched or are currently sketching. Metamodels are defined in a semi-automatic, interactive way by annotating diagram elements and automated model analysis. Our approach requires no metamodeling expertise and supports the co-evolution of models and meta-models.

Requirements elicitation is widely seen as a crucial step towards delivering successful software. In the context of emerging cloud systems, the question is whether and how the elicitation process differs from that used for traditional systems, and if the current methods suffice. We interviewed 19 cloud providers to gain an in-depth understanding of the state of practice with regard to the adoption and implementation of existing elicitation methods. The results of this exploratory study show that, whereas a few cloud providers try to implement and adapt traditional methods, the large majority uses ad-hoc approaches for identifying consumer needs. There are various causes for this situation, ranging from consumer reachability issues and previous failed attempts, to a complete lack of development strategy. The study suggests that only a small number of the current techniques can be applied successfully in cloud systems, hence showing a need to research new ways of supporting cloud providers. The main contribution of this work lies in revealing what elicitation methods are used by cloud providers and clarifying the challenges related to requirements elicitation posed by the cloud paradigm. Further, we identify some key features for cloud-specific elicitation methods.

Early stage requirements models are often documented using paper and pencil-based approaches. In our current research, we are exploring lightweight modeling tools and approaches that could provide a beneficial alternative. We have developed the FlexiSketch tool prototype which combines support for free-form sketching with lightweight metamodeling capabilities. This creates the possibility for an automatic transcription of the documented information in later modeling stages. The tool is designed to be used on tablet devices.

Mobile devices such as Smartphones and Internet Tablets have become an integral part of our life. We can install applications providing various functionalities. Our research focuses on an application which enables end-users to blog requirements in situ. The gathered end-user needs can be seen as a starting point for the development of applications and the evolution of mobile platforms.

End-user involvement in software engineering is an ambivalent topic. However, novel paradigms such as service-oriented computing suggest more active end-user involvement to gather individual needs for software personalization. In this paper, we present a mobile requirements elicitation tool which enables end-users to blog needs in situ without analysts' facilitation.

Eliciting requirements on-site is challenging as analysts have to simultaneously observe the environment, interact with people and operate RE tools. We have been exploring the use of context-aware technologies to provide better guidance and support for on-site analysts. Our context-aware Mobile Scenario Presenter tool guides analysts by automatically highlighting scenario events relevant to the currently observed work task.

Researchers highlight end-user involvement in system design as an important concept for developing useful and usable solutions. However, end-user involvement in software engineering is still an open-ended topic. Novel paradigms such as service-oriented computing strengthen the need for more active end-user involvement in order to provide systems that are tailored to individual end-user needs. Our work is based on the fact that the majority of end-users are familiar with mobile devices and use an increasing number of mobile applications. A mobile tool enabling end-user led requirements elicitation could be just one of many applications installed on end-users' mobile devices. In this paper, we present a framework of end-user involvement in requirements elicitation which motivates our research. The main contribution of our research is a tool-supported requirements elicitation approach allowing end-users to document needs in situ. Furthermore, we present first evaluation results to highlight the feasibility of on-site end-user led requirements elicitation.

This scientific evaluation paper investigates the effectiveness of different scenario forms and uses on requirements discovery. Lt reports results from the application of scenario tools during the specification of requirements on socio-technical systems to improve the environmental impact of aircraft operations at a regional UK airport. Stakeholders walked through scenarios in both text and visual simulation form, and discovered requirements during workshops and whilst observing actors in their workplace. Results revealed both qualitative and quantitative differences in discovered requirements that have potential implications for models of scenario-based requirements discovery and the design of scenario tools.

Scenarios are widely and successfully used to discover requirements for software-intensive systems. Recent advances in mobile computing technologies mean that mobile tools can support scenario-based techniques in the workplace, with potential benefits to requirements processes. To explore this idea we have been developing the Mobile Scenario Presenter (MSP) tool and used it successfully in a number of evaluation studies and projects. The MSP supports analysts working in the field to better understand the work context of a future system 's end users. The interactive tool demo allows RE experts to actively use the MSP to explore its capabilities and benefits.

In this paper we show how Theory-W and the WinWin requirements negotiation approach have influenced software engineering education in a number of institutions worldwide. After a short summary of Theory-W and the WinWin negotiation model, processes, and tools the paper discusses how students can benefit from WinWin in their software engineering education. We explore different options for teaching the approach and present concrete examples and experiences from different universities

Recent advances in mobile computing technologies mean that mobile tools have the potential to support scenario-based techniques in the workplace, with potential benefits to requirements processes. However, mobile requirements engineering (RE) tools are a new idea, and little is known about their advantages and weaknesses. This paper reports empirical research to explore the use of mobile RE tools in practice. It describes a mobile scenario tool that we developed to discover requirements directly in the user's work context. It also describes the results from 3 evaluation studies that demonstrate that these tools can support workplace requirements discovery and documentation, although mobile RE tools pose new challenges that remain to be overcome

Software tools that support or automate software engineering tasks are typically available on traditional desktop-based workstations. In contrast, mobile tools for requirements engineers offer considerable potential. In the last few years the capabilities of mobile devices such as personal digital assistants (PDAs) have advanced considerably. These devices now provide faster processing, increased storage, and improved connectivity. Hence, mobile computing will become a dominant computing paradigm. These developments let us envision mobile tools for RE that are sophisticated enough to be used in real-world projects.