@inproceedings{PalixLawallThomasetal.2010, author = {Palix, Nicolas and Lawall, Julia L. and Thomas, Ga{\"e}l and Muller, Gilles}, title = {How Often do Experts Make Mistakes?}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41327}, year = {2010}, abstract = {Large open-source software projects involve developers with a wide variety of backgrounds and expertise. Such software projects furthermore include many internal APIs that developers must understand and use properly. According to the intended purpose of these APIs, they are more or less frequently used, and used by developers with more or less expertise. In this paper, we study the impact of usage patterns and developer expertise on the rate of defects occurring in the use of internal APIs. For this preliminary study, we focus on memory management APIs in the Linux kernel, as the use of these has been shown to be highly error prone in previous work. We study defect rates and developer expertise, to consider e.g., whether widely used APIs are more defect prone because they are used by less experienced developers, or whether defects in widely used APIs are more likely to be fixed.}, language = {en} } @inproceedings{OPUS4-3948, title = {Preface}, editor = {Adams, Bram and Haupt, Michael and Lohmann, Daniel}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41338}, year = {2010}, abstract = {Aspect-oriented programming, component models, and design patterns are modern and actively evolving techniques for improving the modularization of complex software. In particular, these techniques hold great promise for the development of "systems infrastructure" software, e.g., application servers, middleware, virtual machines, compilers, operating systems, and other software that provides general services for higher-level applications. The developers of infrastructure software are faced with increasing demands from application programmers needing higher-level support for application development. Meeting these demands requires careful use of software modularization techniques, since infrastructural concerns are notoriously hard to modularize. Aspects, components, and patterns provide very different means to deal with infrastructure software, but despite their differences, they have much in common. For instance, component models try to free the developer from the need to deal directly with services like security or transactions. These are primary examples of crosscutting concerns, and modularizing such concerns are the main target of aspect-oriented languages. Similarly, design patterns like Visitor and Interceptor facilitate the clean modularization of otherwise tangled concerns. Building on the ACP4IS meetings at AOSD 2002-2009, this workshop aims to provide a highly interactive forum for researchers and developers to discuss the application of and relationships between aspects, components, and patterns within modern infrastructure software. The goal is to put aspects, components, and patterns into a common reference frame and to build connections between the software engineering and systems communities.}, language = {en} } @inproceedings{BynensVanLanduytTruyenetal.2010, author = {Bynens, Maarten and Van Landuyt, Dimitri and Truyen, Eddy and Joosen, Wouter}, title = {Towards reusable aspects: the callback mismatch problem}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41347}, year = {2010}, abstract = {Because software development is increasingly expensive and timeconsuming, software reuse gains importance. Aspect-oriented software development modularizes crosscutting concerns which enables their systematic reuse. Literature provides a number of AOP patterns and best practices for developing reusable aspects based on compelling examples for concerns like tracing, transactions and persistence. However, such best practices are lacking for systematically reusing invasive aspects. In this paper, we present the 'callback mismatch problem'. This problem arises in the context of abstraction mismatch, in which the aspect is required to issue a callback to the base application. As a consequence, the composition of invasive aspects is cumbersome to implement, difficult to maintain and impossible to reuse. We motivate this problem in a real-world example, show that it persists in the current state-of-the-art, and outline the need for advanced aspectual composition mechanisms to deal with this.}, language = {en} } @inproceedings{GoltzPieth2010, author = {Goltz, Hans-Joachim and Pieth, Norbert}, title = {A tool for generating partition schedules of multiprocessor systems}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41556}, year = {2010}, abstract = {A deterministic cycle scheduling of partitions at the operating system level is supposed for a multiprocessor system. In this paper, we propose a tool for generating such schedules. We use constraint based programming and develop methods and concepts for a combined interactive and automatic partition scheduling system. This paper is also devoted to basic methods and techniques for modeling and solving this partition scheduling problem. Initial application of our partition scheduling tool has proved successful and demonstrated the suitability of the methods used.}, language = {en} } @phdthesis{Ishebabi2010, author = {Ishebabi, Harold}, title = {Architecture synthesis for adaptive multiprocessor systems on chip}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41316}, school = {Universit{\"a}t Potsdam}, year = {2010}, abstract = {This thesis presents methods for automated synthesis of flexible chip multiprocessor systems from parallel programs targeted at FPGAs to exploit both task-level parallelism and architecture customization. Automated synthesis is necessitated by the complexity of the design space. A detailed description of the design space is provided in order to determine which parameters should be modeled to facilitate automated synthesis by optimizing a cost function, the emphasis being placed on inclusive modeling of parameters from application, architectural and physical subspaces, as well as their joint coverage in order to avoid pre-constraining the design space. Given a parallel program and a set of an IP library, the automated synthesis problem is to simultaneously (i) select processors (ii) map and schedule tasks to them, and (iii) select one or several networks for inter-task communications such that design constraints and optimization objectives are met. The research objective in this thesis is to find a suitable model for automated synthesis, and to evaluate methods of using the model for architectural optimizations. Our contributions are a holistic approach for the design of such systems, corresponding models to facilitate automated synthesis, evaluation of optimization methods using state of the art integer linear and answer set programming, as well as the development of synthesis heuristics to solve runtime challenges.}, language = {en} } @inproceedings{Harrison2010, author = {Harrison, William}, title = {Malleability, obliviousness and aspects for broadcast service attachment}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41389}, year = {2010}, abstract = {An important characteristic of Service-Oriented Architectures is that clients do not depend on the service implementation's internal assignment of methods to objects. It is perhaps the most important technical characteristic that differentiates them from more common object-oriented solutions. This characteristic makes clients and services malleable, allowing them to be rearranged at run-time as circumstances change. That improvement in malleability is impaired by requiring clients to direct service requests to particular services. Ideally, the clients are totally oblivious to the service structure, as they are to aspect structure in aspect-oriented software. Removing knowledge of a method implementation's location, whether in object or service, requires re-defining the boundary line between programming language and middleware, making clearer specification of dependence on protocols, and bringing the transaction-like concept of failure scopes into language semantics as well. This paper explores consequences and advantages of a transition from object-request brokering to service-request brokering, including the potential to improve our ability to write more parallel software.}, language = {en} } @inproceedings{Schrijvers2010, author = {Schrijvers, Tom}, title = {Overview of the monadic constraint programming framework}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41411}, year = {2010}, abstract = {A constraint programming system combines two essential components: a constraint solver and a search engine. The constraint solver reasons about satisfiability of conjunctions of constraints, and the search engine controls the search for solutions by iteratively exploring a disjunctive search tree defined by the constraint program. The Monadic Constraint Programming framework gives a monadic definition of constraint programming where the solver is defined as a monad threaded through the monadic search tree. Search and search strategies can then be defined as firstclass objects that can themselves be built or extended by composable search transformers. Search transformers give a powerful and unifying approach to viewing search in constraint programming, and the resulting constraint programming system is first class and extremely flexible.}, language = {en} } @book{GellerHirschfeldBracha2010, author = {Geller, Felix and Hirschfeld, Robert and Bracha, Gilad}, title = {Pattern Matching for an object-oriented and dynamically typed programming language}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-065-6}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-43035}, publisher = {Universit{\"a}t Potsdam}, pages = {81}, year = {2010}, abstract = {Pattern matching is a well-established concept in the functional programming community. It provides the means for concisely identifying and destructuring values of interest. This enables a clean separation of data structures and respective functionality, as well as dispatching functionality based on more than a single value. Unfortunately, expressive pattern matching facilities are seldomly incorporated in present object-oriented programming languages. We present a seamless integration of pattern matching facilities in an object-oriented and dynamically typed programming language: Newspeak. We describe language extensions to improve the practicability and integrate our additions with the existing programming environment for Newspeak. This report is based on the first author's master's thesis.}, language = {en} } @misc{RepsilberKernTelaaretal.2010, author = {Repsilber, Dirk and Kern, Sabine and Telaar, Anna and Walzl, Gerhard and Black, Gillian F. and Selbig, Joachim and Parida, Shreemanta K. and Kaufmann, Stefan H. E. and Jacobsen, Marc}, title = {Biomarker discovery in heterogeneous tissue samples}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {854}, issn = {1866-8372}, doi = {10.25932/publishup-42934}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-429343}, pages = {17}, year = {2010}, abstract = {Background: For heterogeneous tissues, such as blood, measurements of gene expression are confounded by relative proportions of cell types involved. Conclusions have to rely on estimation of gene expression signals for homogeneous cell populations, e.g. by applying micro-dissection, fluorescence activated cell sorting, or in-silico deconfounding. We studied feasibility and validity of a non-negative matrix decomposition algorithm using experimental gene expression data for blood and sorted cells from the same donor samples. Our objective was to optimize the algorithm regarding detection of differentially expressed genes and to enable its use for classification in the difficult scenario of reversely regulated genes. This would be of importance for the identification of candidate biomarkers in heterogeneous tissues. Results: Experimental data and simulation studies involving noise parameters estimated from these data revealed that for valid detection of differential gene expression, quantile normalization and use of non-log data are optimal. We demonstrate the feasibility of predicting proportions of constituting cell types from gene expression data of single samples, as a prerequisite for a deconfounding-based classification approach. Classification cross-validation errors with and without using deconfounding results are reported as well as sample-size dependencies. Implementation of the algorithm, simulation and analysis scripts are available. Conclusions: The deconfounding algorithm without decorrelation using quantile normalization on non-log data is proposed for biomarkers that are difficult to detect, and for cases where confounding by varying proportions of cell types is the suspected reason. In this case, a deconfounding ranking approach can be used as a powerful alternative to, or complement of, other statistical learning approaches to define candidate biomarkers for molecular diagnosis and prediction in biomedicine, in realistically noisy conditions and with moderate sample sizes.}, language = {en} } @article{BergesHubwieser2010, author = {Berges, Marc and Hubwieser, Peter}, title = {Vorkurse in objektorientierter Programmierung}, series = {Commentarii informaticae didacticae : (CID)}, journal = {Commentarii informaticae didacticae : (CID)}, number = {4}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1868-0844}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-64299}, pages = {13 -- 22}, year = {2010}, abstract = {Die Studienanf{\"a}nger der Informatik haben in Deutschland sehr unterschiedliche Grundkenntnisse in der Programmierung. Dies f{\"u}hrt immer wieder zu Schwierigkeiten in der Ausrichtung der Einf{\"u}hrungsveranstaltungen. An der TU M{\"u}nchen wird seit dem Wintersemester 2008/2009 nun eine neue Art von Vorkursen angeboten. In nur 2,5 Tagen erstellen die Teilnehmer ein kleines objektorientiertes Programm. Dabei arbeiten sie weitestgehend alleine, unterst{\"u}tzt von einem studentischen Tutor. In dieser Arbeit sollen nun das Konzept der sogenannten „Vorprojekte" sowie erste Forschungsans{\"a}tze vorgestellt werden}, language = {de} }