@article{HirschfeldKawarnura2006, author = {Hirschfeld, Robert and Kawarnura, Katsuya}, title = {Dynamic service adaptation}, series = {Software : practice \& experience}, volume = {36}, journal = {Software : practice \& experience}, number = {11-12}, publisher = {Wiley}, address = {Chichester}, issn = {0038-0644}, doi = {10.1002/spe.766}, pages = {1115 -- 1131}, year = {2006}, abstract = {Change can be observed in our environment and in the technology we build. While changes in the environment happen continuously and implicitly, our technology has to be kept in sync with the changing world around it. Although we can prepare for some of the changes for most of them we cannot. This is especially true for next-generation mobile communication systems that are expected to support the creation of a ubiquitous society where virtually everything is connected and made available within an organic information network. Resources will frequently join or leave the network, new types of media or new combinations of existing types will be used to interact and cooperate, and services will be tailored to preferences and needs of individual customers to better meet their needs. This paper outlines our research in the area of dynamic service adaptation to provide concepts and technologies allowing for such environments. Copyright (C) 2006 John Wiley \& Sons, Ltd.}, language = {en} } @article{ReinRamsonLinckeetal.2017, author = {Rein, Patrick and Ramson, Stefan and Lincke, Jens and Felgentreff, Tim and Hirschfeld, Robert}, title = {Group-Based Behavior Adaptation Mechanisms in Object-Oriented Systems}, series = {IEEE software}, volume = {34}, journal = {IEEE software}, number = {6}, publisher = {Inst. of Electr. and Electronics Engineers}, address = {Los Alamitos}, issn = {0740-7459}, doi = {10.1109/MS.2017.4121224}, pages = {78 -- 82}, year = {2017}, abstract = {Dynamic and distributed systems require behavior adaptations for groups of objects. Group-based behavior adaptation mechanisms scope adaptations to objects matching conditions beyond class membership. The specification of groups can be explicit or implicit.}, language = {en} } @article{PerscheidSiegmundTaeumeletal.2017, author = {Perscheid, Michael and Siegmund, Benjamin and Taeumel, Marcel and Hirschfeld, Robert}, title = {Studying the advancement in debugging practice of professional software developers}, series = {Software Quality Journal}, volume = {25}, journal = {Software Quality Journal}, publisher = {Springer}, address = {Dordrecht}, issn = {0963-9314}, doi = {10.1007/s11219-015-9294-2}, pages = {83 -- 110}, year = {2017}, abstract = {In 1997, Henry Lieberman stated that debugging is the dirty little secret of computer science. Since then, several promising debugging technologies have been developed such as back-in-time debuggers and automatic fault localization methods. However, the last study about the state-of-the-art in debugging is still more than 15 years old and so it is not clear whether these new approaches have been applied in practice or not. For that reason, we investigate the current state of debugging in a comprehensive study. First, we review the available literature and learn about current approaches and study results. Second, we observe several professional developers while debugging and interview them about their experiences. Third, we create a questionnaire that serves as the basis for a larger online debugging survey. Based on these results, we present new insights into debugging practice that help to suggest new directions for future research.}, language = {en} } @article{ReinTaeumelHirschfeld2017, author = {Rein, Patrick and Taeumel, Marcel and Hirschfeld, Robert}, title = {Making the domain tangible}, series = {Design Thinking Research}, journal = {Design Thinking Research}, publisher = {Springer}, address = {New York}, isbn = {978-3-319-60967-6}, doi = {10.1007/978-3-319-60967-6_9}, pages = {171 -- 194}, year = {2017}, abstract = {Programmers collaborate continuously with domain experts to explore the problem space and to shape a solution that fits the users' needs. In doing so, all parties develop a shared vocabulary, which is above all a list of named concepts and their relationships to each other. Nowadays, many programmers favor object-oriented programming because it allows them to directly represent real-world concepts and interactions from the vocabulary as code. However, when existing domain data is not yet represented as objects, it becomes a challenge to initially bring existing domain data into object-oriented systems and to keep the source code readable. While source code might be comprehensible to programmers, domain experts can struggle, given their non-programming background. We present a new approach to provide a mapping of existing data sources into the object-oriented programming environment. We support keeping the code of the domain model compact and readable while adding implicit means to access external information as internal domain objects. This should encourage programmers to explore different ways to build the software system quickly. Eventually, our approach fosters communication with the domain experts, especially at the beginning of a project. When the details in the problem space are not yet clear, the source code provides a valuable, tangible communication artifact.}, language = {en} } @book{NiephausFelgentreffHirschfeld2017, author = {Niephaus, Fabio and Felgentreff, Tim and Hirschfeld, Robert}, title = {Squimera}, number = {120}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-422-7}, doi = {10.25932/publishup-40338}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-403387}, publisher = {Universit{\"a}t Potsdam}, pages = {92}, year = {2017}, abstract = {Programmierwerkzeuge, die verschiedene Programmiersprachen unterst{\"u}tzen und sich konsistent bedienen lassen, sind hilfreich f{\"u}r Softwareentwickler, weil diese sich nicht erst mit neuen Werkzeugen vertraut machen m{\"u}ssen, wenn sie in einer neuen Sprache entwickeln wollen. Außerdem ist es n{\"u}tzlich, verschiedene Programmiersprachen in einer Anwendung kombinieren zu k{\"o}nnen, da Entwickler dann Softwareframeworks und -bibliotheken nicht in der jeweiligen Sprache nachbauen m{\"u}ssen und stattdessen bestehende Software wiederverwenden k{\"o}nnen. Dennoch haben Entwickler eine sehr große Auswahl, wenn sie nach Werkzeugen suchen, die teilweise zudem speziell nur f{\"u}r eine Sprache ausgelegt sind. Einige integrierte Entwicklungsumgebungen unterst{\"u}tzen verschiedene Programmiersprachen, k{\"o}nnen aber h{\"a}ufig keine konsistente Bedienung ihrer Werkzeuge gew{\"a}hrleisten, da die jeweiligen Ausf{\"u}hrungsumgebungen der Sprachen zu verschieden sind. Dar{\"u}ber hinaus gibt es bereits Mechansimen, die es erlauben, Programme aus anderen Sprachen in einem Programm wiederzuverwenden. Dazu werden h{\"a}ufig das Betriebssystem oder eine Netzwerkverbindung verwendet. Programmierwerkzeuge unterst{\"u}tzen jedoch h{\"a}ufig eine solche Indirektion nicht und sind deshalb nur eingeschr{\"a}nkt nutzbar bei beispielsweise Debugging Szenarien. In dieser Arbeit stellen wir einen neuartigen Ansatz vor, der das Programmiererlebnis in Bezug auf das Arbeiten mit mehreren dynamischen Programmiersprachen verbessern soll. Dazu verwenden wir die Werkzeuge einer Smalltalk Programmierumgebung wieder und entwickeln eine virtuelle Ausf{\"u}hrungsumgebung, die verschiedene Sprachen gleichermaßen unterst{\"u}tzt. Der auf unserem Ansatz basierende Prototyp Squimera demonstriert, dass es m{\"o}glich ist, Programmierwerkzeuge in der Art wiederzuverwenden, sodass sie sich f{\"u}r verschiedene Programmiersprachen gleich verhalten und somit die Arbeit f{\"u}r Entwickler vereinfachen. Außerdem erm{\"o}glicht Squimera einfaches Wiederverwenden und dar{\"u}ber hinaus das Verschmischen von in unterschiedlichen Sprachen geschriebenen Softwarebibliotheken und -frameworks und erlaubt dabei zus{\"a}tzlich Debugging {\"u}ber mehrere Sprachen hinweg.}, language = {en} } @book{ReschkeTaeumelPapeetal.2018, author = {Reschke, Jakob and Taeumel, Marcel and Pape, Tobias and Niephaus, Fabio and Hirschfeld, Robert}, title = {Towards version control in object-based systems}, volume = {121}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-430-2}, issn = {1613-5652}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-410812}, publisher = {Universit{\"a}t Potsdam}, pages = {100}, year = {2018}, abstract = {Version control is a widely used practice among software developers. It reduces the risk of changing their software and allows them to manage different configurations and to collaborate with others more efficiently. This is amplified by code sharing platforms such as GitHub or Bitbucket. Most version control systems track files (e.g., Git, Mercurial, and Subversion do), but some programming environments do not operate on files, but on objects instead (many Smalltalk implementations do). Users of such environments want to use version control for their objects anyway. Specialized version control systems, such as the ones available for Smalltalk systems (e.g., ENVY/Developer and Monticello), focus on a small subset of objects that can be versioned. Most of these systems concentrate on the tracking of methods, classes, and configurations of these. Other user-defined and user-built objects are either not eligible for version control at all, tracking them involves complicated workarounds, or a fixed, domain-unspecific serialization format is used that does not equally suit all kinds of objects. Moreover, these version control systems that are specific to a programming environment require their own code sharing platforms; popular, well-established platforms for file-based version control systems cannot be used or adapter solutions need to be implemented and maintained. To improve the situation for version control of arbitrary objects, a framework for tracking, converting, and storing of objects is presented in this report. It allows editions of objects to be stored in an exchangeable, existing backend version control system. The platforms of the backend version control system can thus be reused. Users and objects have control over how objects are captured for the purpose of version control. Domain-specific requirements can be implemented. The storage format (i.e. the file format, when file-based backend version control systems are used) can also vary from one object to another. Different editions of objects can be compared and sets of changes can be applied to graphs of objects. A generic way for capturing and restoring that supports most kinds of objects is described. It models each object as a collection of slots. Thus, users can begin to track their objects without first having to implement version control supplements for their own kinds of objects. The proposed architecture is evaluated using a prototype implementation that can be used to track objects in Squeak/Smalltalk with Git. The prototype improves the suboptimal standing of user objects with respect to version control described above and also simplifies some version control tasks for classes and methods as well. It also raises new problems, which are discussed in this report as well.}, language = {en} } @book{BeckmannHildebrandJascheketal.2019, author = {Beckmann, Tom and Hildebrand, Justus and Jaschek, Corinna and Krebs, Eva and L{\"o}ser, Alexander and Taeumel, Marcel and Pape, Tobias and Fister, Lasse and Hirschfeld, Robert}, title = {The font engineering platform}, number = {128}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-464-7}, issn = {1613-5652}, doi = {10.25932/publishup-42748}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427487}, publisher = {Universit{\"a}t Potsdam}, pages = {viii, 115}, year = {2019}, abstract = {Creating fonts is a complex task that requires expert knowledge in a variety of domains. Often, this knowledge is not held by a single person, but spread across a number of domain experts. A central concept needed for designing fonts is the glyph, an elemental symbol representing a readable character. Required domains include designing glyph shapes, engineering rules to combine glyphs for complex scripts and checking legibility. This process is most often iterative and requires communication in all directions. This report outlines a platform that aims to enhance the means of communication, describes our prototyping process, discusses complex font rendering and editing in a live environment and an approach to generate code based on a user's live-edits.}, language = {en} } @book{BeinBraunDaaseetal.2020, author = {Bein, Leon and Braun, Tom and Daase, Bj{\"o}rn and Emsbach, Elina and Matthes, Leon and Stiede, Maximilian and Taeumel, Marcel and Mattis, Toni and Ramson, Stefan and Rein, Patrick and Hirschfeld, Robert and M{\"o}nig, Jens}, title = {SandBlocks}, number = {132}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-482-1}, issn = {1613-5652}, doi = {10.25932/publishup-43926}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-439263}, publisher = {Universit{\"a}t Potsdam}, pages = {viii, 212}, year = {2020}, abstract = {Visuelle Programmiersprachen werden heutzutage zugunsten textueller Programmiersprachen nahezu nicht verwendet, obwohl visuelle Programmiersprachen einige Vorteile bieten. Diese reichen von der Vermeidung von Syntaxfehlern, {\"u}ber die Nutzung konkreter dom{\"a}nenspezifischer Notation bis hin zu besserer Lesbarkeit und Wartbarkeit des Programms. Trotzdem greifen professionelle Softwareentwickler nahezu ausschließlich auf textuelle Programmiersprachen zur{\"u}ck. Damit Entwickler diese Vorteile visueller Programmiersprachen nutzen k{\"o}nnen, aber trotzdem nicht auf die ihnen bekannten textuellen Programmiersprachen verzichten m{\"u}ssen, gibt es die Idee, textuelle und visuelle Programmelemente gemeinsam in einer Programmiersprache nutzbar zu machen. Damit ist dem Entwickler {\"u}berlassen wann und wie er visuelle Elemente in seinem Programmcode verwendet. Diese Arbeit stellt das SandBlocks-Framework vor, das diese gemeinsame Nutzung visueller und textueller Programmelemente erm{\"o}glicht. Neben einer Auswertung visueller Programmiersprachen, zeigt es die technische Integration visueller Programmelemente in das Squeak/Smalltalk-System auf, gibt Einblicke in die Umsetzung und Verwendung in Live-Programmiersystemen und diskutiert ihre Verwendung in unterschiedlichen Dom{\"a}nen.}, language = {de} } @book{BaltzerHradilakPfennigschmidtetal.2021, author = {Baltzer, Wanda and Hradilak, Theresa and Pfennigschmidt, Lara and Prestin, Luc Maurice and Spranger, Moritz and Stadlinger, Simon and Wendt, Leo and Lincke, Jens and Rein, Patrick and Church, Luke and Hirschfeld, Robert}, title = {An individual-centered approach to visualize people's opinions and demographic information}, number = {136}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-504-0}, issn = {1613-5652}, doi = {10.25932/publishup-49145}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-491457}, publisher = {Universit{\"a}t Potsdam}, pages = {326}, year = {2021}, abstract = {The noble way to substantiate decisions that affect many people is to ask these people for their opinions. For governments that run whole countries, this means asking all citizens for their views to consider their situations and needs. Organizations such as Africa's Voices Foundation, who want to facilitate communication between decision-makers and citizens of a country, have difficulty mediating between these groups. To enable understanding, statements need to be summarized and visualized. Accomplishing these goals in a way that does justice to the citizens' voices and situations proves challenging. Standard charts do not help this cause as they fail to create empathy for the people behind their graphical abstractions. Furthermore, these charts do not create trust in the data they are representing as there is no way to see or navigate back to the underlying code and the original data. To fulfill these functions, visualizations would highly benefit from interactions to explore the displayed data, which standard charts often only limitedly provide. To help improve the understanding of people's voices, we developed and categorized 80 ideas for new visualizations, new interactions, and better connections between different charts, which we present in this report. From those ideas, we implemented 10 prototypes and two systems that integrate different visualizations. We show that this integration allows consistent appearance and behavior of visualizations. The visualizations all share the same main concept: representing each individual with a single dot. To realize this idea, we discuss technologies that efficiently allow the rendering of a large number of these dots. With these visualizations, direct interactions with representations of individuals are achievable by clicking on them or by dragging a selection around them. This direct interaction is only possible with a bidirectional connection from the visualization to the data it displays. We discuss different strategies for bidirectional mappings and the trade-offs involved. Having unified behavior across visualizations enhances exploration. For our prototypes, that includes grouping, filtering, highlighting, and coloring of dots. Our prototyping work was enabled by the development environment Lively4. We explain which parts of Lively4 facilitated our prototyping process. Finally, we evaluate our approach to domain problems and our developed visualization concepts. Our work provides inspiration and a starting point for visualization development in this domain. Our visualizations can improve communication between citizens and their government and motivate empathetic decisions. Our approach, combining low-level entities to create visualizations, provides value to an explorative and empathetic workflow. We show that the design space for visualizing this kind of data has a lot of potential and that it is possible to combine qualitative and quantitative approaches to data analysis.}, language = {en} } @book{SeitzLinckeReinetal.2021, author = {Seitz, Klara and Lincke, Jens and Rein, Patrick and Hirschfeld, Robert}, title = {Language and tool support for 3D crochet patterns}, number = {137}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-505-7}, issn = {1613-5652}, doi = {10.25932/publishup-49253}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-492530}, publisher = {Universit{\"a}t Potsdam}, pages = {vii, 94}, year = {2021}, abstract = {Crochet is a popular handcraft all over the world. While other techniques such as knitting or weaving have received technical support over the years through machines, crochet is still a purely manual craft. Not just the act of crochet itself is manual but also the process of creating instructions for new crochet patterns, which is barely supported by domain specific digital solutions. This leads to unstructured and often also ambiguous and erroneous pattern instructions. In this report, we propose a concept to digitally represent crochet patterns. This format incorporates crochet techniques which allows domain specific support for crochet pattern designers during the pattern creation and instruction writing process. As contributions, we present a thorough domain analysis, the concept of a graph structure used as domain specific language to specify crochet patterns and a prototype of a projectional editor using the graph as representation format of patterns and a diagramming system to visualize them in 2D and 3D. By analyzing the domain, we learned about crochet techniques and pain points of designers in their pattern creation workflow. These insights are the basis on which we defined the pattern representation. In order to evaluate our concept, we built a prototype by which the feasibility of the concept is shown and we tested the software with professional crochet designers who approved of the concept.}, language = {en} }