51 research outputs found

    The 6th Conference of PhD Students in Computer Science

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    ISCR Annual Report: Fical Year 2004

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    The 5th Conference of PhD Students in Computer Science

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    Language design for distributed stream processing

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 149-152).Applications that combine live data streams with embedded, parallel, and distributed processing are becoming more commonplace. WaveScript is a domain-specific language that brings high-level, type-safe, garbage-collected programming to these domains. This is made possible by three primary implementation techniques, each of which leverages characteristics of the streaming domain. First, WaveScript employs an evaluation strategy that uses a combination of interpretation and reification to partially evaluate programs into stream dataflow graphs. Second, we use profile-driven compilation to enable many optimizations that are normally only available in the synchronous (rather than asynchronous) dataflow domain. Finally, an empirical, profile-driven approach also allows us to compute practical partitions of dataflow graphs, spreading them across embedded nodes and more powerful servers. We have used our language to build and deploy applications, including a sensor-network for the acoustic localization of wild animals such as the Yellow-Bellied marmot. We evaluate WaveScript's performance on this application, showing that it yields good performance on both embedded and desktop-class machines. Our language allowed us to implement the application rapidly, while outperforming a previous C implementation by over 35%, using fewer than half the lines of code. We evaluate the contribution of our optimizations to this success. We also evaluate WaveScript's ability to extract parallelism from this and other applications.by Ryan Rhodes Newton.Ph.D

    Software evolution: hypergraph based model of solution space andhmeta-search

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    A hypergraph based model of software evolution is proposed. The model uses software assets, and any other higher order patterns, as reusable components. We will use software product lines and software factories concepts as the engineering state-of-the-art framework to model evolution. Using those concepts, the solution space is sliced into sub-spaces using equivalence classes and their corresponding isomorphism. Any valid graph expansions will be required to retain information by being sub-graph isomorphic, forming a chain to a solution. We are also able to traverse the resulting modelled space. A characteristic set of operators and operands is used to find solutions that would be compatible. The result is in a structured manner to explore the combinatorial solution space, classifying solutions as part of families hierarchies. Using a software engineering interpretation a viable prototype implementation of the model has been created. It uses configuration files that are used as design-time instruments analogous to software factory schemas. These form configuration layers we call fragments. These fragments convert to graph node metadata to later allow complex graph queries. A profusion of examples of the modelling and its visualisation options are provided for better understanding. An example of automated generation of a configuration, using current Google Cloud assets, has been generated and added to the prototype. It illustrates automation possibilities by using harvested web data, and later, creating a custom isomorphic relation as a configuration. The feasibility of the model is thus demonstrated. The formalisation adds the rigour needed to further facilitate automation of software craftsmanship. Based on the model operation, we propose a concept of organic growth based on evolution. Evolution events are modelled after incremental change messages. This is communication efficient and it is shown to adhere to the Representational State Transfer architectural style. Finally, The Cloud is presented as an evolved solution part of a family, from the original concept of The Web

    Definition of a Type System for Generic and Reflective Graph Transformations

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    This thesis presents the extension of the graph transformation language SDM (Story Driven Modeling) with generic and reflective features as well as the definition of type checking rules for this language. The generic and reflective features aim at improving the reusability and expressiveness of SDM, whereas the type checking rules will ensure the type-safety of graph transformations. This thesis starts with an explanation of the relevant concepts as well as a description of the context in order to provide the reader with a better understanding of our approach. The model driven development of software, today considered as the standard paradigm, is generally based on the use of domain-specific languages such as MATLAB Simulink and Stateflow. To increase the quality, the reliability,and the efficiency of models and the generated code, checking and elimination of detected guideline violations defined in huge catalogues has become an essential, but error-prone and time-consuming task in the development process. The MATE/MAJA projects, which are based on the use of the SDM language, aim at an automation of this task for MATLAB Simulink/Stateflow models. Modeling guidelines can be specified on a very high level of abstraction by means of graph transformations. Moreover, these specifications allow for the generation of guideline checking tools. Unfortunately, most graph transformation languages do not offer appropriate concepts for reuse of specification fragments - a MUST, when we deal with hundreds of guidelines. As a consequence we present an extension of the SDM language which supports the definition of generic rewrite rules and combines them with the reflective programming mechanisms of Java and the model repository interface standard JMI. Reusability and expressiveness are not the only aspects we want to improve. Another fundamental aspect of graph transformations must be ensured: their correctness in order to prevent type errors while executing the transformations. Checking and testing the graph transformations manually would ruin the benefit obtained by the automation of the guideline checking and by the generic and reflective features. Therefore, we propose in this work a type-checking method for graph transformations. We introduce a new notation for rules of inference and define a type system for SDM. We also proposed an algorithm to apply this type system. We illustrate and evaluate both contributions of our work by applying them on running examples. Proposals for other additional SDM features as well as for possible improvements of our type checking open new perspectives and future research to pursue our work

    Tools and Selected Applications

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    Defining and simulating open-ended novelty: requirements, guidelines, and challenges

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    The open-endedness of a system is often defined as a continual production of novelty. Here we pin down this concept more fully by defining several types of novelty that a system may exhibit, classified as variation, innovation, and emergence. We then provide a meta-model for including levels of structure in a system’s model. From there, we define an architecture suitable for building simulations of open-ended novelty-generating systems and discuss how previously proposed systems fit into this framework. We discuss the design principles applicable to those systems and close with some challenges for the community

    A Model-Driven Architecture based Evolution Method and Its Application in An Electronic Learning System

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    Software products have been racing against aging problem for most of their lifecycles, and evolution is the most effective and efficient solution to this problem. Model-Driven Architecture (MDA) is a new technique for software product for evolving development and reengineering methods. The main steps for MDA are to establish models in different levels and phases, therefore to solve the challenges of requirement and technology change. However, there is only a standard established by Object Management Group (OMG) but without a formal method and approach. Presently, MDA is widely researched in both industrial and research areas, however, there is still without a smooth approach to realise it especially in electronic learning (e-learning) system due to the following reasons: (1) models’ transformations are hard to realise because of lack of tools, (2) most of existing mature research results are working for business and government services but not education area, and (3) most of existing model-driven researches are based on Model-Driven Development (MDD) but not MDA because of OMG standard’s preciseness. Hence, it is worth to investigate an MDA-based method and approach to improve the existing software development approach for e-learning system. Due to the features of MDA actuality, a MDA-based evolution method and approach is proposed in this thesis. The fundamental theories of this research are OMG’s MDA standard and education pedagogical knowledge. Unified Modelling Language (UML) and Unified Modelling Language Profile are hired to represent the information of software system from different aspects. This study can be divided into three main parts: MDA-based evolution method and approach research, Platform-Independent Model (PIM) to Platform-Specific Model (PSM) transformation development, and MDA-based electronic learning system evolution. Top-down approach is explored to develop models for e-learning system. A transformation approach is developed to generate Computation Independent Model (CIM), Platform-Independent Model (PIM), and Platform-Specific Model (PSM); while a set of transformation rules are defined following MDA standard to support PSM’ s generation. In addition, proposed method is applied in an e-learning system as a case study with the prototype rules support. In the end, conclusions are drawn based on analysis and further research directions are discussed as well. The kernel contributions are the proposed transformation rules and its application in electronic learning system
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