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Component based software development (CBSD) and aspectoriented software development (AOSD) are two complementary approaches. However, existing proposals for integrating aspects into component models are direct transposition of object-oriented AOSD techniques to components. In this article, we propose a new approach based on views. Our proposal introduces crosscutting components quite naturally and can be integrated into different component models.
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.
Preface
(2010)
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.
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.
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.
Die Ergebnisse aus dreißig Fallstudien in deutschen Biotechnologieunternehmen wurden genutzt, um einen Leitfaden für Biotechnologieunternehmen zu entwickeln, der die Unternehmen im Prozess der Internationalisierung unterstützt. Der Leitfaden zur Internationalisierung umfasst: • Beschreibung relevanter Auslandsmärkte (USA, UK, Frankreich, Indien) • Auswahl geeigneter Auslandsmärkte • Ermittlung einer geeigneten Markteintrittsform • Darstellung von Good Practice in der Internationalisierung • Managementempfehlungen Im Rahmen der Fallstudien wurde die USA als wichtigster Auslandsmarkt für Dienstleistungen in der roten Biotechnologie (DLrBT) identifiziert, Großbritannien als wichtigster europäischer Markt. Auch Frankreich wurde als ein bedeutender Markt in Europa ermittelt, der für die Unternehmen jedoch sehr schwer zu bearbeiten ist aufgrund von hohen Markteintrittsbarrieren. Des weiteren wurde Indien, neben den genannten Märkten, als ein emergenter Markt in den Leitfaden aufgenommen. Mit dem Internationalisierungsleitfaden wurde ein Instrument entwickelt, das zu einer objektiveren Bewertung von Chancen und Risiken des Markteintritts in einen bestimmten Zielmarkt einen Beitrag leistet. Der Anwender wird angehalten sich systematisch mit den folgenden Themenkomplexen zu beschäftigen: • Was sind relevante k.o.-Kriterien für Zielmärkte? • Welche Umsatzchancen birgt der Zielmarkt? • Wie sind die generellen Verhältnisse im Zielmarkt (z.B. Käuferverhalten)? • Auf welche Akteure treffe ich im Zielmarkt (Kunden, Wettbewerber, Mittler)? • Wie trete ich am besten in den Markt ein? Im Leitfaden wird auch aufgezeigt, wie die Internationalisierung in „Good Practice“ Unternehmen der Biotechnologie abgelaufen ist. Die empirische Grundlage dafür bilden die Ergebnisse der Fallstudienarbeit. • Wie ist die Internationalisierung im Detail abgelaufen? • Wie erfolgte der Eintritt in Auslandsmärkte? • Was waren die Gründe für diesen Ablauf bzw. für diese Vorgehensweise? • Was waren die größten Barrieren? Im Leitfaden werden Rahmenbedingungen und Internationalisierungsstrategien diskutiert und das Born-Global Verhalten dem stufenartigen Vorgehen in der Internationalisierung gegenübergestellt und Managementempfehlungen präsentiert. Im Leitfaden werden Checklisten zur Länderauswahl, zur Einschätzung von Markteintrittsbarrieren und unternehmensinternen Kriterien für die Zielmarkterschließung angeboten. Der Leitfaden zur Internationalisierung ist eine praktische Handlungsanleitung für das Management von Biotechnologieunternehmen.
Der vorliegende Band 23 der Reihe "LLF-Berichte" des Zentrums für Lehrerbildung der Universität Potsdam enthält eine Zusammenschau der Evaluation des Projektes Reinventing Education . Web 2.0 Tools to foster Teacher Collaboration in Brandenburg ONLIFE / Online-Lehrerzusammenarbeit zur Förderung der Individualisierung des Lernens an Schulen. Die Evaluation des Projektes umfasste den Zeitraum 2006-2008. Der vorliegende Band stellt die beiden Hauptphasen aus 2007 und 2008 ausführlich dar. Die Erkenntnisse dieses Projektes haben Modellcharakter für analoge Projekte in der Bundesrepublik und regen zu einem Erfahrungsaustausch zur online-gestützen Lehrerzusammenarbeit auf Bundesebene an.
CHAMP (CHAllenging Minisatellite Payload) is a German small satellite mission to study the earth's gravity field, magnetic field and upper atmosphere. Thanks to the good condition of the satellite so far, the planned 5 years mission is extended to year 2009. The satellite provides continuously a large quantity of measurement data for the purpose of Earth study. The measurements of the magnetic field are undertaken by two Fluxgate Magnetometers (vector magnetometer) and one Overhauser Magnetometer (scalar magnetometer) flown on CHAMP. In order to ensure the quality of the data during the whole mission, the calibration of the magnetometers has to be performed routinely in orbit. The scalar magnetometer serves as the magnetic reference and its readings are compared with the readings of the vector magnetometer. The readings of the vector magnetometer are corrected by the parameters that are derived from this comparison, which is called the scalar calibration. In the routine processing, these calibration parameters are updated every 15 days by means of scalar calibration. There are also magnetic effects coming from the satellite which disturb the measurements. Most of them have been characterized during tests before launch. Among them are the remanent magnetization of the spacecraft and fields generated by currents. They are all considered to be constant over the mission life. The 8 years of operation experience allow us to investigate the long-term behaviors of the magnetometers and the satellite systems. According to the investigation, it was found that for example the scale factors of the FGM show obvious long-term changes which can be described by logarithmic functions. The other parameters (offsets and angles between the three components) can be considered constant. If these continuous parameters are applied for the FGM data processing, the disagreement between the OVM and the FGM readings is limited to \pm1nT over the whole mission. This demonstrates, the magnetometers on CHAMP exhibit a very good stability. However, the daily correction of the parameter Z component offset of the FGM improves the agreement between the magnetometers markedly. The Z component offset plays a very important role for the data quality. It exhibits a linear relationship with the standard deviation of the disagreement between the OVM and the FGM readings. After Z offset correction, the errors are limited to \pm0.5nT (equivalent to a standard deviation of 0.2nT). We improved the corrections of the spacecraft field which are not taken into account in the routine processing. Such disturbance field, e.g. from the power supply system of the satellite, show some systematic errors in the FGM data and are misinterpreted in 9-parameter calibration, which brings false local time related variation of the calibration parameters. These corrections are made by applying a mathematical model to the measured currents. This non-linear model is derived from an inversion technique. If the disturbance field of the satellite body are fully corrected, the standard deviation of scalar error \triangle B remains about 0.1nT. Additionally, in order to keep the OVM readings a reliable standard, the imperfect coefficients of the torquer current correction for the OVM are redetermined by solving a minimization problem. The temporal variation of the spacecraft remanent field is investigated. It was found that the average magnetic moment of the magneto-torquers reflects well the moment of the satellite. This allows for a continuous correction of the spacecraft field. The reasons for the possible unknown systemic error are discussed in this thesis. Particularly, both temperature uncertainties and time errors have influence on the FGM data. Based on the results of this thesis the data processing of future magnetic missions can be designed in an improved way. In particular, the upcoming ESA mission Swarm can take advantage of our findings and provide all the auxiliary measurements needed for a proper recovery of the ambient magnetic field.
Im Mittelpunkt des fünften Bandes der Reihe Perspektiven historischen Denkens und Lernens steht eine Epoche des Umbruchs und des Überganges, die Frühe Neuzeit. Traditionelle historische Begriffe werden auf den Prüfstand neuerer Forschungsansätze gestellt. Der französischen Revolution werden neue Aspekte beigefügt, wie die Mentalitätsgeschichte. Auch die Amerikanische Revolution nimmt einen gebührenden Platz ein. Ganz neue Facetten der Geschichte enthält das abschließende Kapitel zur Kulturgeschichte.
STG decomposition is a promising approach to tackle the complexity problems arising in logic synthesis of speed independent circuits, a robust asynchronous (i.e. clockless) circuit type. Unfortunately, STG decomposition can result in components that in isolation have irreducible CSC conflicts. Generalising earlier work, it is shown how to resolve such conflicts by introducing internal communication between the components via structural techniques only.