Prestanda har historiskt sett alltid varit av betydelse för nyttjandet av datorer, vilket lett till att processorutvecklare har tagit fram flera olika metoder för att klämma ut mer processorkraft från processorn. Ett av dessa koncept är processorns cacheminne, som ansvarar för att lagra data processorn förväntar sig att behöva inom en snar framtid. Om cacheminnet nyttjats väl så innebär detta att processorn can behandla data i en mycket snabbare takt, vilket direkt påverkar prestanda. På grund av detta vill utvecklare gärna skriva kod som nyttjar cacheminnet till fullo. Detta är inte alltid en enkel uppgift, då de programmeringsmönster och beteenden utvecklaren måste anpassa sig till går att anse vara klumpiga för utvecklaren. Den här studioen kommer utforska möjligheterna att sammanfoga cachevänliga programmeringskoncept med utvecklarvänlig syntax, vilket resulterar i ett programmeringsspråk som är både läsbart, skrivbart samt effektivt med hänsyn till processorns cacheminne. För att lyckas med denna uppgift har studier på mönster inom minnesåtkomst, befintliga programmeringsspråk och kompilatordesign genomförts. Slutprodukten är ett språl vid namn Ghoul som implementerar cachevänliga koncept på en syntaktisk nivå, komplett med en fungerande kompilator. Utdata från denna kompilator blev senare prestandatestad för att avgöra huruvida de koncept språket introducerar har en märkbar påverkan på prestandan av program skrivna i detta språk. Testen visade att de tidigare nämnda konceptet direkt visar ett inflytande på hastigheten data kan behandlas i språket. / Performance has historically always been of importance to computing, and as such, processor developers have brought up several different methods to squeeze out more processing power from the processor. One of these concepts is the presence of a CPU cache memory, whose responsibility is to hold data the processor expects it might use soon. To utilize the cache well means that the processor can compute data at a much higher rate, resulting in a direct impact on performance. Therefore, it follows that it is in the developer’s best interest to write code capable of utilizing the cache memory to its full extent. This is not always an easy task however, as the patterns and style of programming the developer may need to adapt to can come of as cumbersome. This study will explore the possibilities of merging cache-friendly programming concepts with a developer-friendly syntax, resulting in a language that is both readable, writeable as well as efficient in regards to the processor cache. In order to accomplish this task, studies of memory access patterns, existing programming languages and compiler design has been performed. The end product is a language called Ghoul which successfully implements cache-friendly concepts on a syntactic level, complete with a working compiler. Outputs from this compiler were later benchmarked to assert that the concepts introduced had a measurable impact on the performance of programs written in Ghoul, showing that the aforementioned syntactical concepts indeed directly influence the speed at which data can be processed.

To increase market penetration, mobile software makers support their popular applications on all major software platforms, which currently include Android, iOS, and Windows Phone. Although these platforms often offer a drastically different look and feel, cross-platform applications deliver the same core functionality to the end user. Maintaining and evolving such applications currently requires replicating all the changes across all supported variants, a laborious and intellectually taxing enterprise. The state-of-the-practice automated source translation tools fall short, as they are incapable of handling the structural and idiomatic differences of the software frameworks driving major mobile platforms. In addition, popular mobile applications increasingly make use of distributed resources. Certain domains, including social networking, productivity enhancement, and gaming, require different application instances to continuously exchange information with each other. The current state of the art in supporting communication across heterogeneous mobile devices requires the programmer to write platform-specific, low-level API calls that are hard not only to develop but also to evolve and maintain. This thesis reports on the findings of two complementary research activities, conducted with the goal of facilitating the development and communication across heterogeneous mobile devices: (1) a programming model and runtime support for heterogeneous device-to-device communication across mobile applications; (2) a source code recommendation system that synthesizes code snippets from web-based programming resources, based on the functionality written for Android or iOS and vice versa. The conceptual and practical advancements of this research have potential to benefit fellow researchers as well as mobile software developers and users. / Master of Science

With the rise of electronic integration between organizations, the need for a precise specification of interaction behavior increases. Information systems, replacing interaction previously carried out by humans via phone, faxes and emails, require a precise specification for handling all possible situations. Such interaction behavior is described in process choreographies. Choreographies enumerate the roles involved, the allowed interactions, the message contents and the behavioral dependencies between interactions. Choreographies serve as interaction contract and are the starting point for adapting existing business processes and systems or for implementing new software components. As a thorough analysis and comparison of choreography modeling languages is missing in the literature, this thesis introduces a requirements framework for choreography languages and uses it for comparing current choreography languages. Language proposals for overcoming the limitations are given for choreography modeling on the conceptual and on the technical level. Using an interconnection modeling style, behavioral dependencies are defined on a per-role basis and different roles are interconnected using message flow. This thesis reveals a number of modeling "anti-patterns" for interconnection modeling, motivating further investigations on choreography languages following the interaction modeling style. Here, interactions are seen as atomic building blocks and the behavioral dependencies between them are defined globally. Two novel language proposals are put forward for this modeling style which have already influenced industrial standardization initiatives. While avoiding many of the pitfalls of interconnection modeling, new anomalies can arise in interaction models. A choreography might not be realizable, i.e. there does not exist a set of interacting roles that collectively realize the specified behavior. This thesis investigates different dimensions of realizability. / Elektronische Integration zwischen Organisationen erfordert eine präzise Spezifikation des Interaktionsverhaltens: Informationssysteme, die Kommunikation per Telefon, Fax und Email ablösen, können nicht so flexibel und selbständig auf Ausnahmesituationen reagieren wie Menschen. Choreographien ermöglichen es, Interaktionsverhalten genau zu spezifizieren. Diese Modelle zählen die beteiligten Rollen, die erlaubten Interaktionen, Nachrichteninhalte und Verhaltensabhängigkeiten auf und dienen somit als Interaktionsvertrag zwischen den Organisationen. Auch als Ausgangspunkt für eine Anpassung existierender Prozesse und Systeme sowie für die Implementierung neuer Softwarekomponenten finden Choreographien Anwendung. Da ein Vergleich von Choreographiemodellierungssprachen in der Literatur bislang fehlt, präsentiert diese Arbeit einen Anforderungskatalog, der als Basis für eine Evaluierung existierender Sprachen angewandt wird. Im Kern führt diese Arbeit Spracherweiterungen ein, um die Schwächen existierender Sprachen zu überwinden. Die vorgestellten Erweiterungen adressieren dabei Modellierung auf konzeptioneller und auf technischer Ebene. Beim Verlinkungsmodellierungsstil werden Verhaltensabhängigkeiten innerhalb der beteiligten Rollen spezifiziert und das Interaktionsverhalten entsteht durch eine Verlinkung der Kommunikationsaktivitäten. Diese Arbeit stellt einige "Anti-Pattern" für die Verlinkungsmodellierung vor, welche wiederum Untersuchungen bzgl. Choreographiesprachen des Interaktionsmodellierungsstils motivieren. Hier werden Interaktionen als atomare Blöcke verstanden und Verhaltensabhängigkeiten werden global definiert. Diese Arbeit führt zwei neue Choreographiesprachen dieses zweiten Modellierungsstils ein, welche bereits in industrielle Standardisierungsinitiativen eingeflossen sind. Während auf der einen Seite zahlreiche Fallstricke der Verlinkungsmodellierung umgangen werden, können in Interaktionsmodellen allerdings neue Anomalien entstehen. Eine Choreographie kann z.B. "unrealisierbar" sein, d.h. es ist nicht möglich interagierende Rollen zu finden, die zusammen genommen das spezifizierte Verhalten abbilden. Dieses Phänomen wird in dieser Arbeit über verschiedene Dimensionen von Realisierbarkeit untersucht.

This dissertation defines "modular-objective coupling", and shows that programming language designs which imply reduced modular-objective coupling reduce complexity of remodularizations--behaviour-preserving restructurings for which the only intended goals are to change program source code structure. We explicitly distinguish between two points of view on program structure: modular structure--the structure of a program as a set of static text documents, and objective structure--the structure of a program as a dynamic computational model during execution. We define modular-objective coupling as the degree to which changes in modular structure imply changes to objective structure, for a given programming language. We use the term remodularization to refer to any behaviour-preserving source code restructuring, for which the only intended goal is to change modular structure. We argue that programming languages with strong modular-objective coupling introduce accidental complexity into remodularizations, by requiring complex objective structure changes to achieve intended modular structure changes. Our claim is that a programming language design which implies reduced modular-objective coupling reduces remodularization complexity in the language. To validate this claim, we first present SubjectJ, a subject-oriented programming system that extends Java. The design of Java implies strong modular-objective coupling, while SubjectJ is designed for reduced modular-objective coupling. We then perform a series of remodularization case studies comparing Java and SubjectJ. Our results suggest that remodularizations are less complex in SubjectJ.

This dissertation defines "modular-objective coupling", and shows that programming language designs which imply reduced modular-objective coupling reduce complexity of remodularizations--behaviour-preserving restructurings for which the only intended goals are to change program source code structure. We explicitly distinguish between two points of view on program structure: modular structure--the structure of a program as a set of static text documents, and objective structure--the structure of a program as a dynamic computational model during execution. We define modular-objective coupling as the degree to which changes in modular structure imply changes to objective structure, for a given programming language. We use the term remodularization to refer to any behaviour-preserving source code restructuring, for which the only intended goal is to change modular structure. We argue that programming languages with strong modular-objective coupling introduce accidental complexity into remodularizations, by requiring complex objective structure changes to achieve intended modular structure changes. Our claim is that a programming language design which implies reduced modular-objective coupling reduces remodularization complexity in the language. To validate this claim, we first present SubjectJ, a subject-oriented programming system that extends Java. The design of Java implies strong modular-objective coupling, while SubjectJ is designed for reduced modular-objective coupling. We then perform a series of remodularization case studies comparing Java and SubjectJ. Our results suggest that remodularizations are less complex in SubjectJ.

This dissertation defines "modular-objective coupling", and shows that programming language designs which imply reduced modular-objective coupling reduce complexity of remodularizations--behaviour-preserving restructurings for which the only intended goals are to change program source code structure. We explicitly distinguish between two points of view on program structure: modular structure--the structure of a program as a set of static text documents, and objective structure--the structure of a program as a dynamic computational model during execution. We define modular-objective coupling as the degree to which changes in modular structure imply changes to objective structure, for a given programming language. We use the term remodularization to refer to any behaviour-preserving source code restructuring, for which the only intended goal is to change modular structure. We argue that programming languages with strong modular-objective coupling introduce accidental complexity into remodularizations, by requiring complex objective structure changes to achieve intended modular structure changes. Our claim is that a programming language design which implies reduced modular-objective coupling reduces remodularization complexity in the language. To validate this claim, we first present SubjectJ, a subject-oriented programming system that extends Java. The design of Java implies strong modular-objective coupling, while SubjectJ is designed for reduced modular-objective coupling. We then perform a series of remodularization case studies comparing Java and SubjectJ. Our results suggest that remodularizations are less complex in SubjectJ. / Science, Faculty of / Computer Science, Department of / Graduate

Visual scripting languages are used as alternatives to text programming to make coding easier. Visual programming languages provide a structure and a guidance that does not exist in text programming, which should make them easier to code with. Some users do however find that the structure in visual scripting languages makes it cumbersome to code. To find a design of visual scripting that subvert this and has a better user experience than contemporary designs, a prototype of a visual scripting interface was developed using an iterative design and testing cycle. When a final prototype had been developed, it was tested to see how it compared to text programming. From the tests performed, a few teachings were discovered. If-statements that grow perpendicularly to the rest of the code fit more information on the screen at the same time and can feel more natural and easier to parse for some users. Having a help menu with syntax-help makes it so that users do not have to leave the program, which increases programming speed. The visual coding elements in a visual scripting language need to be coloured such that the most important parts are the most visible; otherwise users have a hard time parsing the code. Showing existing variables that are in scope gives the user a good overview of what variables they can use. Having help menus where elements can be clicked to insert them at the user's text cursor reduces the chance of misspelling variables and gives the user confidence in the correctness of the code. Having visual coding elements that can change depending on context or by using toggles can make coding more intuitive and faster. / <p>Examensarbetet är utfört vid Institutionen för teknik och naturvetenskap (ITN) vid Tekniska fakulteten, Linköpings universitet</p>

In the vision of Ambient Intelligence, people are assisted in their everyday activities through the proactive, opportunistic support of non-intrusive computing devices offering intuitive interaction modalities. The usefulness and quality of delivered services can be improved considerably if the devices are able to adapt their behaviour according to sensed changes in their surrounding environment, both at the physical and logical levels. This interplay between context-awareness and dynamic software adaptability is key to the construction of applications that are smart with respect to user needs. Unfortunately, most current applications do not reach this level of adaptability, due to a lack of appropriate programming technology. Most applications exhibit fixed functionality and seldom do they sense their environment and adapt their services in a context-aware fashion. Many chances of delivering improved services to users and network peers are thus missed. This dissertation presents a programming model to ease the construction of applications that can react to changes in their execution context by adapting their behaviour dynamically. The starting point of our research is the development of novel language abstractions and the adaptation of existing abstractions to render context-aware, self-adaptable applications easier to develop. We demonstrate that a simple yet powerful computation model readily provides the needed support, leading to straightforward application code that is not concerned with context adaptation, behaviour that can be adapted dynamically to different contexts in a non-intrusive fashion, and context-aware applications with software architectures that are not biased towards context adaptation ---rather, they can be designed freely according to their domain. The proposed computation model is realised through the Ambience programming language, and its underlying open implementation, the Ambient Object System. A small-step operational semantics describes it formally. Much in the vein of prototype-based programming, the model has been designed with simplicity and concreteness in mind. It is highly dynamic, featuring dynamic (multiple) dispatch, dynamic inheritance, dynamic typing, and dynamic method scoping. Application logic adaptation is enabled by means of an intuitive, first-class reification of context that is straightforwardly connected to dynamic behaviour selection. We describe needed management techniques for such context, and a few programming guidelines on how to develop context-aware applications using our approach. The approach is validated by showing its application in a number of scenarios inspired on Ambient Intelligence.

This thesis studies the design of deep-inference deductive systems. In the systems with deep inference, in contrast to traditional proof-theoretic systems, inference rules can be applied at any depth inside logical expressions. Deep applicability of inference rules provides a rich combinatorial analysis of proofs. Deep inference also makes it possible to design deductive systems that are tailored for computer science applications and otherwise provably not expressible. By applying the inference rules deeply, logical expressions can be manipulated starting from their sub-expressions. This way, we can simulate analytic proofs in traditional deductive formalisms. Furthermore, we can also construct much shorter analytic proofs than in these other formalisms. However, deep applicability of inference rules causes much greater nondeterminism in proof construction. This thesis attacks the problem of dealing with nondeterminism in proof search while preserving the shorter proofs that are available thanks to deep inference. By redesigning the deep inference deductive systems, some redundant applications of the inference rules are prevented. By introducing a new technique which reduces nondeterminism, it becomes possible to obtain a more immediate access to shorter proofs, without breaking certain proof theoretical properties such as cutelimination. Different implementations presented in this thesis allow to perform experiments on the techniques that we developed and observe the performance improvements. Within a computation-as-proof-search perspective, we use deepinference deductive systems to develop a common proof-theoretic language to the two fields of planning and concurrency.

The intricate concepts of ad-hoc polymorphism and overloading permeate the field of programming languages despite their somewhat nebulous definitions. With the perspective afforded by the state of the art, object-oriented Fortress programming language, this thesis presents a contemporary account of ad-hoc polymorphism and overloading in theory and in practice. Common language constructs are reinterpreted with a new emphasis on overloading as a key facility. Furthermore, concrete problems with overloading in Fortress, encountered during the author's experience in the development of the language, are presented with an emphasis on the ad hoc nature of their solutions. / text