In recent years, the development of multi-core CPUs and GPUs with many cores has taken precedence over an increase in clock frequency. Therefore, writing parallel programs for multi-core and many-core systems becomes increasingly important. Due to the lack of inherently parallel language features in most programming languages, today many programs are written sequentially and then enhanced with special pragmas or framework calls hinting parallelizable parts of code. This hints are then used to modify and extend the code with parallel constructs in a preprocessing step. If it is crucial to optimize the run time of a program, the code generated by this step has to be inspected an manually tuned. To keep the original and the transformed code artifacts synchronized, an editor with a round-trip engineering (RTE) system can be used. RTE propagates changes made in the source artifacts to the generated artifacts and vice versa. One tool that can be used to expand pragmas to parallelized source code is the invasive software composition framework SkAT. SkAT-based tools use reference attribute grammars (RAGs) to compose code fragments according to a composition program written in Java. To facilitate the creation of SkAT-based tools, a minimal composition system framework SkAT/Minimal on to of the SkAT core contains mechanisms to enable the incremental building of such tools. The principle of island parsing is employed to be able to express just as much of a language as is necessary for composition. In this work, composition systems based on SkAT/Minimal are targeted. The task is split into two parts: first, approaches for RTE are analyzed and a concept for a RTE system is created. The focus lies on the analysis of features and requirements of existing RTE approaches and a thorough investigation of all relevant steps required to implement such a system for SkAT/Minimal. The second part of the task is the creation and evaluation of a prototypical implementation of the system.

Introduktionen av AJAX har möjliggjort skapandet av dynamiska webbapplikationer på Internet. Dessa dynamiska webbapplikationer bygger på att skicka data mellan klient och server med hjälp av asynkrona förfrågningar. Detta görs med hjälp av ett serialiseringsformat som används för att kompaktera data och möjliggöra kommunikation mellan olika programmeringsspråk. Binära serialiseringsformat har konsistent visat sig prestera bättre än de textbaserade alternativen på plattformar som tillåter binär transport av data. AJAX är en plattform som endast tillåter textbaserad transport av data. Detta arbete syftar till att jämföra prestandan av textbaserade och binära serialiseringsformat för AJAX med hjälp av bland annat round-trip time. Arbetet har utförts genom att skapa en webbapplikation som utför prestandamätningar med hjälp av olika datamängder med varierande storlek och innehåll. Resultaten visar att binära serialiseringsformat endast skulle kunna vara ett tänkbart alternativ när det rör sig om webbapplikationer som skickar mycket sifferdominant data.

IETF proposes the Differentiated Service(DiffServ) architecture for next-generation QoS networks. The main features of a DiffServ network are high scalability and compatibility. However, lacking of supporting QoS for individual flows becomes a problem. To remedy this problem, we propose an effective TCP transmission (ETCP) scheme based on the characteristics of TCP. The goal of this thesis is to make TCP transmission more effective. Because of the network complexity, we need to modify both the Ingress and Egress nodes. At Ingress node, we measure TCP congestion window(cwnd) and Round Trip Time(RTT), while at Egress node we monitor the throughput and embed a feedback ratio into TCP header of the acknowledge packets. When the throughput is below or over the target throughput, we adjust DSCP dynamically. The adjustment depends on both measured TCP congestion window and RTT. Each DSCP value is mapped with a delay time through Delayed-FIFO. Changing the delay time in Ingress node, we are able to control TCP transmission associated with RTT more effectively. For the purpose of the demonstration, we implement our scheme on Linux platform. We discuss the performance difference between the theoretical and practical results through experiments. Besides, from the implementation, we have shown that our proposed architecture is workable and compatible with today¡¦s network environment.

In recent years, the development of multi-core CPUs and GPUs with many cores has taken precedence over an increase in clock frequency. Therefore, writing parallel programs for multi-core and many-core systems becomes increasingly important. Due to the lack of inherently parallel language features in most programming languages, today many programs are written sequentially and then enhanced with special pragmas or framework calls hinting parallelizable parts of code. This hints are then used to modify and extend the code with parallel constructs in a preprocessing step. If it is crucial to optimize the run time of a program, the code generated by this step has to be inspected an manually tuned. To keep the original and the transformed code artifacts synchronized, an editor with a round-trip engineering (RTE) system can be used. RTE propagates changes made in the source artifacts to the generated artifacts and vice versa. One tool that can be used to expand pragmas to parallelized source code is the invasive software composition framework SkAT. SkAT-based tools use reference attribute grammars (RAGs) to compose code fragments according to a composition program written in Java. To facilitate the creation of SkAT-based tools, a minimal composition system framework SkAT/Minimal on to of the SkAT core contains mechanisms to enable the incremental building of such tools. The principle of island parsing is employed to be able to express just as much of a language as is necessary for composition. In this work, composition systems based on SkAT/Minimal are targeted. The task is split into two parts: first, approaches for RTE are analyzed and a concept for a RTE system is created. The focus lies on the analysis of features and requirements of existing RTE approaches and a thorough investigation of all relevant steps required to implement such a system for SkAT/Minimal. The second part of the task is the creation and evaluation of a prototypical implementation of the system.:1 Introduction 1 1.1 Motivation 1 1.2 Scope 2 1.3 Contributions 2 1.4 Organization 2 2 Background 5 2.1 Fundamentals 6 2.1.1 Syntax Trees 6 2.1.2 Parsing and Unparsing 6 2.2 Attribute Grammars 9 2.2.1 Reference Attribute Grammars 10 2.2.2 Reference Attribute Grammars in SkAT 10 2.3 Composition Systems 12 2.3.1 Software Composition Systems 13 2.3.2 Invasive Software Composition 13 2.3.3 SkAT 15 2.3.4 Template-based Code Generation 16 2.4 Round-trip Engineering 17 2.4.1 Motivation For Round-trip Engineering 17 2.4.2 Concepts of RTE 18 3 Analysis of RTE Approaches 19 3.1 Automatic Round-trip Engineering 19 3.2 RTE In Aspect Weaving Systems 21 3.2.1 CST Graftings 21 3.2.2 Update Propagation in Aspect Weaving Systems 22 3.3 RTE in Invasive Software Composition Systems 23 3.3.1 Tracing Composition Program Execution 23 3.3.2 Backpropagation of Changes 24 3.3.3 Implementation in the Reuseware Framework 26 3.4 Managing Fragments in RTE 27 3.5 Evaluation of RTE Approaches 28 4 Tracing in SkAT 31 4.1 Requirements 31 4.1.1 Objectives 32 4.1.2 Functional and Nonfunctional Requirements 32 4.2 Concept 33 4.3 Implementation 34 5 Building an RTE-editor Prototype 37 5.1 Prerequisites 37 5.2 Requirements 39 5.3 Concept 40 5.3.1 AST Interface 41 5.3.2 Composer Interface 41 5.3.3 Generating the Output 41 5.3.4 The Prototype Skeleton 42 5.4 Implementation 43 6 Designing an RTE-editor 49 6.1 Replay 50 6.2 AST Modifications 50 6.2.1 Modification Types 51 6.2.2 Detecting Modification Types 52 6.3 Origin Inference 53 6.3.1 Inference for Updated Elements 53 6.3.2 Inference for Deleted Elements 54 6.3.3 Inference for Inserted Elements 54 6.4 Gap Edit Problem 54 6.4.1 Inference in SkAT 57 6.4.2 Multiple Source Fragments 57 6.5 Applying Modifications 58 6.5.1 Propagating Terminal Updates 60 6.5.2 Propagating Non-terminal Updates 61 6.5.3 Propagating Deletions 62 6.5.4 Propagating Insertions 62 6.5.5 Propagating Composed Modifications 62 6.6 Adapting SkAT Composition Programs 63 7 Evaluation and Outlook on Future Works 65 7.1 Fragment Versioning 65 7.2 Composition Program DSL 66 7.3 Structured Editors 68 7.4 SkAT RTE System 68 Appendices 71 List of Figures 73 List of Listings 75 List of Abbreviations 77 Bibliography 79 CD Content 83

Software is becoming more and more part of our daily life and makes it easier, e.g., in the areas of communication and infrastructure. Model-driven software development forms the basis for the development of software through the use and combination of different models, which serve as central artifacts in the software development process. In this respect, model-driven software development comprises the process from requirement analysis through design to software implementation. This set of models with their relationships to each other forms a so-called megamodel. Due to the overlapping of the models, inconsistencies occur between the models, which must be removed. Therefore, round-trip engineering is a mechanism for synchronizing models and is the foundation for ensuring consistency between models. Most of the current approaches in this area, however, work with outdated batch-oriented transformation mechanisms, which no longer meet the requirements of more complex, long-living, and ever-changing software. In addition, the creation of megamodels is time-consuming and complex, and they represent unmanageable constructs for a single user. The aim of this thesis is to create a megamodel by means of easy-to-learn mechanisms and to achieve its consistency by removing redundancy on the one hand and by incrementally managing consistency relationships on the other hand. In addition, views must be created on the parts of the megamodel to extract them across internal model boundaries. To achieve these goals, the role concept of Kühn in 2014 is used in the context of model-driven software development, which was developed in the Research Training Group 'Role-based Software Infrastructures for continuous-context-sensitive Systems.' A contribution of this work is a role-based single underlying model approach, which enables the generation of views on heterogeneous models. Besides, an approach for the synchronization of different models has been developed, which enables the role-based single underlying model approach to be extended by new models. The combination of these two approaches creates a runtime-adaptive megamodel approach that can be used in model-driven software development. The resulting approaches will be evaluated based on an example from the literature, which covers all areas of the work. In addition, the model synchronization approach will be evaluated in connection with the Transformation Tool Contest Case from 2019.

This thesis aims to improve sales forecasting in the context of passenger airlines. We study two important issues that could potentially improve forecasting accuracy: day-to-day price change rather than price itself, and linking flights that are likely to be considered as pairs for a round trip by passengers; we refer to the latter as the Round-Trip Model (RTM). We find that price change is a significant variable regardless of days remaining to flight in the last three weeks to flight departure, which opens the possibility of planning for revenue maximizing price change patterns. We also find that the RTM can improve the precision of the forecasting models, and provide an improved pricing strategy for planners. In the study of the effect of price change on sales, analysis of variance is applied; finite regression mixture models were tested to identify linked traffic in the two directions and the linked flights on a route in reverse directions; adaptive neuro-fuzzy inference system (ANFIS) is applied to develop comparative models for studying sales effect between price and price change, and one-way versus round-trip models. The price change model demonstrated more robust results with comparable estimation errors, and the concept model for the round-trip with only one linked flight reduced estimation error by 5%. This empirical study is performed on a database with 22,900 flights which was obtained from a major North American passenger airline.

In these few years, gradually Internet develops to wideband, multimedia is being used on video or music. In addition, the use of IP Multicast must be based on the deployment of routers, which is too difficult to arrange. Utilities of Application Layer Multicast is in the middle and just between IP Multicast and Unicast.Therefore, in this paper, Application Layer Multicast is still worth to study it. In this paper, is applied effectively build the Application Layer Multicast. Control through the IP Anycast Technique, we can lower the time for host join the Multicast Tree. Every host can join the nearest cluster. We use the hierarchical cluster-based Method in order to serve more hosts. This concept about cluster can substantially decrease control overhead. The Complete Binary Trees lower the cluster leader¡¦s burden, also phased RTT decided effectively the transit sequence. In Summary, associate techniques with methods, to make up the defects from NICE and I-Zigzag.

<p>Denna rapport undersöker krav, tagna från ett ramverk för evaluering av CASE-verktyg i ett kontextuellt sammanhang, i två representativa CASE-verktyg. Ramverket utnyttjar en modell som föreslagits av Lundell och Lings för att extrahera både krav och förväntningar som en organisation (www.it.volvo.com) hade på vad ett CASE-verktyg är och kan utföra.</p><p>Ramverket extraherar krav i ett organisationell kontext, dvs. utvärderingen utfördes innan verktyget som evaluerades användes i organisationen. Detta indikerar på att kraven inte är knutna till ett specifikt verktyg, samt att CASE-verktyg inte säkert stödjer dessa krav.</p><p>Resultatet för denna rapport är att viss semantisk förlust uppstod vid transformering av kod och modeller.</p>

Every day data communication networks carry more and more information, which sometimes is very important and needs to be delivered in time. To achieve that, data transfer networks must meet quality requirements that are formed in SLA contracts between clients and service providers. Supplied data transfer link’s quality is described by worldwide defined quality metrics, which include: one way delay, IP delay variation, link loss and round trip time. In order to measure these metrics, special software was created during projects “QoS monitoring system” first phase. This paper continues the project and explores available tuning methods for created software including time synchronization and mobility problems in order to provide better accuracy with higher mobility. New system topology and time offset correction using measurement packets were proposed during the analysis part. Possible system improvements were put to test in order to evaluate the efficiency during the experiment.

This thesis aims to improve sales forecasting in the context of passenger airlines. We study two important issues that could potentially improve forecasting accuracy: day-to-day price change rather than price itself, and linking flights that are likely to be considered as pairs for a round trip by passengers; we refer to the latter as the Round-Trip Model (RTM). We find that price change is a significant variable regardless of days remaining to flight in the last three weeks to flight departure, which opens the possibility of planning for revenue maximizing price change patterns. We also find that the RTM can improve the precision of the forecasting models, and provide an improved pricing strategy for planners. In the study of the effect of price change on sales, analysis of variance is applied; finite regression mixture models were tested to identify linked traffic in the two directions and the linked flights on a route in reverse directions; adaptive neuro-fuzzy inference system (ANFIS) is applied to develop comparative models for studying sales effect between price and price change, and one-way versus round-trip models. The price change model demonstrated more robust results with comparable estimation errors, and the concept model for the round-trip with only one linked flight reduced estimation error by 5%. This empirical study is performed on a database with 22,900 flights which was obtained from a major North American passenger airline.