@inproceedings{KiyLucke2014, author = {Kiy, Alexander and Lucke, Ulrike}, title = {Learning analytic tools in practical comparison}, series = {DeLFI Workshops of the 12th e-Learning Conference of the German Computer Society, DeLFI 2014; Freiburg; Germany; 15 September 2014 through 15 September 2014 CEUR Workshop Proceedings}, volume = {2014}, booktitle = {DeLFI Workshops of the 12th e-Learning Conference of the German Computer Society, DeLFI 2014; Freiburg; Germany; 15 September 2014 through 15 September 2014 CEUR Workshop Proceedings}, number = {1227}, editor = {Rensing, C. and Trahasch, S.}, publisher = {Technical University of Aachen}, address = {Aachen}, issn = {1613-0073}, pages = {104 -- 111}, year = {2014}, language = {en} } @incollection{KiyLuckeZoerner2014, author = {Kiy, Alexander and Lucke, Ulrike and Zoerner, Dietmar}, title = {An adaptive personal learning environment architecture}, series = {Architecture of Computing Systems - ARCS 2014 Lecture Notes in Computer Science}, volume = {2014}, booktitle = {Architecture of Computing Systems - ARCS 2014 Lecture Notes in Computer Science}, number = {8350}, publisher = {Springer}, isbn = {978-3-319-04890-1}, publisher = {Universit{\"a}t Potsdam}, pages = {60 -- 71}, year = {2014}, abstract = {Institutions are facing the challenge to integrate legacy systems with steadily growing new ones, using different technologies and interaction patterns. With the demand of offering the best potential of all systems, several not matching systems including their functions have to be aggregated and offered in a useable way. This paper presents an adaptive, generalizable and self-organized Personal Learning Environment (PLE) framework with the potential to integrate several heterogeneous services using a service-oriented architecture. First, a general overview over the field is given, followed by the description of the core components of the PLE framework. A prototypical implementation is presented. Finally, it's shown how the PLE framework can be dynamically adapted to a changing system environment, reflecting experiences from first user studies.}, language = {en} } @inproceedings{KnothKiy2014, author = {Knoth, Alexander Henning and Kiy, Alexander}, title = {(Self-)confident through the introductory study phase with the Reflect App}, series = {CEUR Workshop Proceedings}, booktitle = {CEUR Workshop Proceedings}, number = {1227}, publisher = {CEUR-WS}, address = {Freiburg}, issn = {1613-0073}, pages = {172 -- 179}, year = {2014}, language = {en} } @article{GaroufiKoller2014, author = {Garoufi, Konstantina and Koller, Alexander}, title = {Generation of effective referring expressions in situated context}, series = {Language, cognition and neuroscience}, volume = {29}, journal = {Language, cognition and neuroscience}, number = {8}, publisher = {Routledge, Taylor \& Francis Group}, address = {Abingdon}, issn = {2327-3798}, doi = {10.1080/01690965.2013.847190}, pages = {986 -- 1001}, year = {2014}, abstract = {In task-oriented communication, references often need to be effective in their distinctive function, that is, help the hearer identify the referent correctly and as effortlessly as possible. However, it can be challenging for computational or empirical studies to capture referential effectiveness. Empirical findings indicate that human-produced references are not always optimally effective, and that their effectiveness may depend on different aspects of the situational context that can evolve dynamically over the course of an interaction. On this basis, we propose a computational model of effective reference generation which distinguishes speaker behaviour according to its helpfulness to the hearer in a certain situation, and explicitly aims at modelling highly helpful speaker behaviour rather than speaker behaviour invariably. Our model, which extends the planning-based paradigm of sentence generation with a statistical account of effectiveness, can adapt to the situational context by making this distinction newly for each new reference. We find that the generated references resemble those of effective human speakers more closely than references of baseline models, and that they are resolved correctly more often than those of other models participating in a shared-task evaluation with human hearers. Finally, we argue that the model could serve as a methodological framework for computational and empirical research on referential effectiveness.}, language = {en} } @article{SchickBojahrHerzogetal.2014, author = {Schick, Daniel and Bojahr, Andre and Herzog, Marc and Shayduk, Roman and von Korff Schmising, Clemens and Bargheer, Matias}, title = {Udkm1Dsim-A simulation toolkit for 1D ultrafast dynamics in condensed matter}, series = {Computer physics communications : an international journal devoted to computational physics and computer programs in physics}, volume = {185}, journal = {Computer physics communications : an international journal devoted to computational physics and computer programs in physics}, number = {2}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0010-4655}, doi = {10.1016/j.cpc.2013.10.009}, pages = {651 -- 660}, year = {2014}, abstract = {The UDKM1DSIM toolbox is a collection of MATLAB (MathWorks Inc.) classes and routines to simulate the structural dynamics and the according X-ray diffraction response in one-dimensional crystalline sample structures upon an arbitrary time-dependent external stimulus, e.g. an ultrashort laser pulse. The toolbox provides the capabilities to define arbitrary layered structures on the atomic level including a rich database of corresponding element-specific physical properties. The excitation of ultrafast dynamics is represented by an N-temperature model which is commonly applied for ultrafast optical excitations. Structural dynamics due to thermal stress are calculated by a linear-chain model of masses and springs. The resulting X-ray diffraction response is computed by dynamical X-ray theory. The UDKM1DSIM toolbox is highly modular and allows for introducing user-defined results at any step in the simulation procedure. Program summary Program title: udkm1Dsim Catalogue identifier: AERH_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AERH_v1_0.html Licensing provisions: BSD No. of lines in distributed program, including test data, etc.: 130221 No. of bytes in distributed program, including test data, etc.: 2746036 Distribution format: tar.gz Programming language: Matlab (MathWorks Inc.). Computer: PC/Workstation. Operating system: Running Matlab installation required (tested on MS Win XP -7, Ubuntu Linux 11.04-13.04). Has the code been vectorized or parallelized?: Parallelization for dynamical XRD computations. Number of processors used: 1-12 for Matlab Parallel Computing Toolbox; 1 - infinity for Matlab Distributed Computing Toolbox External routines: Optional: Matlab Parallel Computing Toolbox, Matlab Distributed Computing Toolbox Required (included in the package): mtimesx Fast Matrix Multiply for Matlab by James Tursa, xml io tools by Jaroslaw Tuszynski, textprogressbar by Paul Proteus Nature of problem: Simulate the lattice dynamics of 1D crystalline sample structures due to an ultrafast excitation including thermal transport and compute the corresponding transient X-ray diffraction pattern. Solution method: Restrictions: The program is restricted to 1D sample structures and is further limited to longitudinal acoustic phonon modes and symmetrical X-ray diffraction geometries. Unusual features: The program is highly modular and allows the inclusion of user-defined inputs at any time of the simulation procedure. Running time: The running time is highly dependent on the number of unit cells in the sample structure and other simulation parameters such as time span or angular grid for X-ray diffraction computations. However, the example files are computed in approx. 1-5 min each on a 8 Core Processor with 16 GB RAM available.}, language = {en} } @article{GieseHildebrandtLambers2014, author = {Giese, Holger and Hildebrandt, Stephan and Lambers, Leen}, title = {Bridging the gap between formal semantics and implementation of triple graph grammars}, series = {Software and systems modeling}, volume = {13}, journal = {Software and systems modeling}, number = {1}, publisher = {Springer}, address = {Heidelberg}, issn = {1619-1366}, doi = {10.1007/s10270-012-0247-y}, pages = {273 -- 299}, year = {2014}, abstract = {The correctness of model transformations is a crucial element for model-driven engineering of high-quality software. A prerequisite to verify model transformations at the level of the model transformation specification is that an unambiguous formal semantics exists and that the implementation of the model transformation language adheres to this semantics. However, for existing relational model transformation approaches, it is usually not really clear under which constraints particular implementations really conform to the formal semantics. In this paper, we will bridge this gap for the formal semantics of triple graph grammars (TGG) and an existing efficient implementation. While the formal semantics assumes backtracking and ignores non-determinism, practical implementations do not support backtracking, require rule sets that ensure determinism, and include further optimizations. Therefore, we capture how the considered TGG implementation realizes the transformation by means of operational rules, define required criteria, and show conformance to the formal semantics if these criteria are fulfilled. We further outline how static and runtime checks can be employed to guarantee these criteria.}, language = {en} } @article{WeiherHirschfeld2014, author = {Weiher, Marcel and Hirschfeld, Robert}, title = {Polymorphic identifiers: uniform resource access in objective-smalltalk}, series = {ACM SIGPLAN notices}, volume = {49}, journal = {ACM SIGPLAN notices}, number = {2}, publisher = {Association for Computing Machinery}, address = {New York}, issn = {0362-1340}, doi = {10.1145/2508168.2508169}, pages = {61 -- 71}, year = {2014}, abstract = {In object-oriented programming, polymorphic dispatch of operations decouples clients from specific providers of services and allows implementations to be modified or substituted without affecting clients. The Uniform Access Principle (UAP) tries to extend these qualities to resource access by demanding that access to state be indistinguishable from access to operations. Despite language features supporting the UAP, the overall goal of substitutability has not been achieved for either alternative resources such as keyed storage, files or web pages, or for alternate access mechanisms: specific kinds of resources are bound to specific access mechanisms and vice versa. Changing storage or access patterns either requires changes to both clients and service providers and trying to maintain the UAP imposes significant penalties in terms of code-duplication and/or performance overhead. We propose introducing first class identifiers as polymorphic names for storage locations to solve these problems. With these Polymorphic Identifiers, we show that we can provide uniform access to a wide variety of resource types as well as storage and access mechanisms, whether parametrized or direct, without affecting client code, without causing code duplication or significant performance penalties.}, language = {en} } @article{NaujokatNeubauerLamprechtetal.2014, author = {Naujokat, Stefan and Neubauer, Johannes and Lamprecht, Anna-Lena and Steffen, Bernhard and Joerges, Sven and Margaria, Tiziana}, title = {Simplicity-first model-based plug-in development}, series = {Software : practice \& experience}, volume = {44}, journal = {Software : practice \& experience}, number = {3}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0038-0644}, doi = {10.1002/spe.2243}, pages = {277 -- 297}, year = {2014}, abstract = {In this article, we present our experience with over a decade of strict simplicity orientation in the development and evolution of plug-ins. The point of our approach is to enable our graphical modeling framework jABC to capture plug-in development in a domain-specific setting. The typically quite tedious and technical plug-in development is shifted this way from a programming task to the modeling level, where it can be mastered also by application experts without programming expertise. We show how the classical plug-in development profits from a systematic domain-specific API design and how the level of abstraction achieved this way can be further enhanced by defining adequate building blocks for high-level plug-in modeling. As the resulting plug-in models can be compiled and deployed automatically, our approach decomposes plug-in development into three phases where only the realization phase requires plug-in-specific effort. By using our modeling framework jABC, this effort boils down to graphical, tool-supported process modeling. Furthermore, we support the automatic completion of process sketches for executability. All this will be illustrated along the most recent plug-in-based evolution of the jABC framework, which witnessed quite some bootstrapping effects.}, language = {en} } @article{TroegerMerzky2014, author = {Troeger, Peter and Merzky, Andre}, title = {Towards standardized job submission and control in infrastructure clouds}, series = {Journal of grid computing}, volume = {12}, journal = {Journal of grid computing}, number = {1}, publisher = {Springer}, address = {Dordrecht}, issn = {1570-7873}, doi = {10.1007/s10723-013-9275-2}, pages = {111 -- 125}, year = {2014}, abstract = {The submission and management of computational jobs is a traditional part of utility computing environments. End users and developers of domain-specific software abstractions often have to deal with the heterogeneity of such batch processing systems. This lead to a number of application programming interface and job description standards in the past, which are implemented and established for cluster and Grid systems. With the recent rise of cloud computing as new utility computing paradigm, the standardized access to batch processing facilities operated on cloud resources becomes an important issue. Furthermore, the design of such a standard has to consider a tradeoff between feature completeness and the achievable level of interoperability. The article discusses this general challenge, and presents some existing standards with traditional cluster and Grid computing background that may be applicable to cloud environments. We present OCCI-DRMAA as one approach for standardized access to batch processing facilities hosted in a cloud.}, language = {en} } @article{HoosLindauerSchaub2014, author = {Hoos, Holger and Lindauer, Marius and Schaub, Torsten H.}, title = {claspfolio 2}, series = {Theory and practice of logic programming}, volume = {14}, journal = {Theory and practice of logic programming}, publisher = {Cambridge Univ. Press}, address = {New York}, issn = {1471-0684}, doi = {10.1017/S1471068414000210}, pages = {569 -- 585}, year = {2014}, abstract = {Building on the award-winning, portfolio-based ASP solver claspfolio, we present claspfolio 2, a modular and open solver architecture that integrates several different portfolio-based algorithm selection approaches and techniques. The claspfolio 2 solver framework supports various feature generators, solver selection approaches, solver portfolios, as well as solver-schedule-based pre-solving techniques. The default configuration of claspfolio 2 relies on a light-weight version of the ASP solver clasp to generate static and dynamic instance features. The flexible open design of claspfolio 2 is a distinguishing factor even beyond ASP. As such, it provides a unique framework for comparing and combining existing portfolio-based algorithm selection approaches and techniques in a single, unified framework. Taking advantage of this, we conducted an extensive experimental study to assess the impact of different feature sets, selection approaches and base solver portfolios. In addition to gaining substantial insights into the utility of the various approaches and techniques, we identified a default configuration of claspfolio 2 that achieves substantial performance gains not only over clasp's default configuration and the earlier version of claspfolio, but also over manually tuned configurations of clasp.}, language = {en} }