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Coupling of the electrical, mechanical and optical response in polymer/liquid-crystal composites
(2010)
Micrometer-sized liquid-crystal (LC) droplets embedded in a polymer matrix may enable optical switching in the composite film through the alignment of the LC director along an external electric field. When a ferroelectric material is used as host polymer, the electric field generated by the piezoelectric effect can orient the director of the LC under an applied mechanical stress, making these materials interesting candidates for piezo-optical devices. In this work, polymer-dispersed liquid crystals (PDLCs) are prepared from poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) and a nematic liquid crystal (LC). The anchoring effect is studied by means of dielectric relaxation spectroscopy. Two dispersion regions are observed in the dielectric spectra of the pure P(VDF-TrFE) film. They are related to the glass transition and to a charge-carrier relaxation, respectively. In PDLC films containing 10 and 60 wt% LC, an additional, bias-field-dependent relaxation peak is found that can be attributed to the motion of LC molecules. Due to the anchoring effect of the LC molecules, this relaxation process is slowed down considerably, when compared with the related process in the pure LC. The electro-optical and piezo-optical behavior of PDLC films containing 10 and 60 wt% LCs is investigated. In addition to the refractive-index mismatch between the polymer matrix and the LC molecules, the interaction between the polymer dipoles and the LC molecules at the droplet interface influences the light-scattering behavior of the PDLC films. For the first time, it was shown that the electric field generated by the application of a mechanical stress may lead to changes in the transmittance of a PDLC film. Such a piezo-optical PDLC material may be useful e.g. in sensing and visualization applications. Compared to a non-polar matrix polymer, the polar matrix polymer exhibits a strong interaction with the LC molecules at the polymer/LC interface which affects the electro-optical effect of the PDLC films and prevents a larger increase in optical transmission.
Mit dem Amtsantritt Barack Obamas wurden nach Jahren schwelender Kriegsgefahr mit dem Iran große Hoffnungen verbunden. Das Papier analysiert die der US-Regierung vorgelegten Iran-Strategiepapiere im Hinblick auf eine Lösung im Iran-Konflikt. Das Spektrum der angedachten Politik reicht von Scheindiplomatie zur Kriegslegitimation bis hin zu selektiver Annäherung. Zum Schluss wird der Frage nachgegangen, inwieweit tatsächlich eine Wende in der Iran-Politik Obamas zu erwarten ist.
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.
Außenpolitik ist von den Werten, dem Selbstverständnis einer Gesellschaft und den ökonomischen Interessen ihrer Volkswirtschaft geprägt. In den ersten beiden Teilen dieses Essays zeigen wir auf, wie Deutschland seine Werte behutsam erneuern sollte und welche Bereiche zur Wahrung seines ökonomischen Wohlstands zentral sind. Auf dieses Fundament setzen wir ein Plädoyer für eine neue außenpolitische Kultur, die Interessen offen debattiert und klar definiert, um sie erfolgreich durchzusetzen.
Reif für die Weltpolitik?
(2010)
Bereits vor zehn Jahren diskutierten wir über die außenpolitische Reife deutscher Eliten. Das Ergebnis war widersprüchlich, kritisch ernüchternd. Gegenwärtig, 20 Jahre nach der deutschen Einheit, ist es an der Zeit, erneut nachzufragen. Die Welt- und Europapolitik sind im Fieber. Die neokonservative Marktwirtschaft – bis vor Kurzem noch siegessicher – erodiert. Die westliche Welt steckt am Beginn des 21. Jahrhunderts in einer Systemkrise. Hektische Gipfel jagen einander, von Kopenhagen über London und Davos bis nach München. Da ist die Frage erlaubt: Wie steht es in solch turbulenten Zeiten eigentlich um die deutsche Außenpolitik?
Tolerierter Schmuggel
(2010)
Grenzen sind soziale Tatsachen, die sich räumlich manifestieren – etwa wenn Schmuggler und Grenzschützer an Grenzübergängen aufeinandertreffen und in ritualisierter Form Bedingungen und Möglichkeiten des Grenzübertritts aushandeln. Das Grenzgeschehen wird in diesem Beitrag in soziologisch-ethnologischer Perspektive am Beispiel des Kaliningrader Grenzgebiets betrachtet.
Selektive Grenzen
(2010)
Die Grenze - historisches Auslaufmodell? Moralische Zumutung? Unabdingbare Tatsache? Meist ist sie eine Art Limes: Durchlässig für den Austausch bestimmter Waren und Personen, zugleich Schutz gegen das Eindringen unerwünschter Fremder. Vielfach erklärtes Ziel ist ein "grenzenloses Europa". Im Innern der EU sind Schlagbäume verschwunden, an den Rändern wird vielerorts abgeschottet. Die Grenzsortierungen der EU sind Thema der aktuellen WeltTrends. Afghanistan und kein Ende? Die Londoner Konferenz verspricht trotz "neuer Strategie" keinen erfolgreichen Neuanfang. "Es wird zunächst schlimmer", so ein hoher deutscher Militär. Alternativen müssen diskutiert werden: WeltTrends bietet den Raum.
Die Analyse vergleicht Installationen von Bruce Nauman und Olafur Eliasson ausgehend von der Fragestellung, wie sich die künstlerischen Performativitätsstrategien der 1960er/70er Jahren und die der zeitgenössischen Kunst in ihren Wirkungen und Effekten unterscheiden lassen. Dabei werden die Positionen der beiden Künstler als paradigmatisch für eine Ästhetik des Performativen angesehen. Neben dem Vergleich der Künstler steht die theoretische Auseinandersetzung mit der Diskursfigur der Performativität sowie deren methodischen Anwendbarkeit in der Kunstwissenschaft im Vordergrund. Während sich Installationen der 1960er/70er Jahre besonders durch die psycho-physische Einwirkung auf die Sinneswahrnehmung des Betrachters auszeichnen und durchaus Schockeffekte beim Betrachter hervorrufen, befasst sich die zeitgenössische Kunstpraxis vornehmlich mit visuellen und poetischen Effekten, die eine kontemplative Rezeptionshaltung des Betrachters einfordern. Bruce Nauman war es ein Anliegen, den tradierten Status des Kunstwerks als ein zu Betrachtendes, das sich durch Begriffe wie Form, Ursprung und Originalität fassen ließ, in Frage zu stellen und stattdessen eine reale leibliche Erfahrung für den Betrachter nachvollziehbar werden zu lassen. Künstlern wie Olafur Eliasson geht es in den künstlerischen Produktionen vor allem um die Wahrnehmung der Wahrnehmung sowie der Erzeugung von Präsenzeffekten. Mit dem Aufkommen solcher Verfahren wurde deutlich, dass performative Installationen nach anderen Beschreibungsformen verlangten und, dass diese durch eine Ästhetik des Performativen gefasst werden können. Wie genau vollzieht sich der Wandel von den performativen Strategien der 1960er/70er Jahre zu denen der zeitgenössischen Installationskünstlern? Verläuft dieser vom Schock zur Poesie?
The difference-list technique is described in literature as effective method for extending lists to the right without using calls of append/3. There exist some proposals for automatic transformation of list programs into differencelist programs. However, we are interested in construction of difference-list programs by the programmer, avoiding the need of a transformation step. In [GG09] it was demonstrated, how left-recursive procedures with a dangling call of append/3 can be transformed into right-recursion using the unfolding technique. For simplification of writing difference-list programs using a new cons/2 procedure was introduced. In the present paper, we investigate how efficieny is influenced using cons/2. We measure the efficiency of procedures using accumulator technique, cons/2, DCG’s, and difference lists and compute the resulting speedup in respect to the simple procedure definition using append/3. Four Prolog systems were investigated and we found different behaviour concerning the speedup by difference lists. A result of our investigations is, that an often advice given in the literature for avoiding calls append/3 could not be confirmed in this strong formulation.
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.
In the most abstract definition of its operational semantics, the declarative and concurrent programming language CHR is trivially non-terminating for a significant class of programs. Common refinements of this definition, in closing the gap to real-world implementations, compromise on declarativity and/or concurrency. Building on recent work and the notion of persistent constraints, we introduce an operational semantics avoiding trivial non-termination without compromising on its essential features.
Different properties of programs, implemented in Constraint Handling Rules (CHR), have already been investigated. Proving these properties in CHR is fairly simpler than proving them in any type of imperative programming language, which triggered the proposal of a methodology to map imperative programs into equivalent CHR. The equivalence of both programs implies that if a property is satisfied for one, then it is satisfied for the other. The mapping methodology could be put to other beneficial uses. One such use is the automatic generation of global constraints, at an attempt to demonstrate the benefits of having a rule-based implementation for constraint solvers.
Deductive databases need general formulas in rule bodies, not only conjuctions of literals. This is well known since the work of Lloyd and Topor about extended logic programming. Of course, formulas must be restricted in such a way that they can be effectively evaluated in finite time, and produce only a finite number of new tuples (in each iteration of the TP-operator: the fixpoint can still be infinite). It is also necessary to respect binding restrictions of built-in predicates: many of these predicates can be executed only when certain arguments are ground. Whereas for standard logic programming rules, questions of safety, allowedness, and range-restriction are relatively easy and well understood, the situation for general formulas is a bit more complicated. We give a syntactic analysis of formulas that guarantees the necessary properties.
Abstract interpretation-based model checking provides an approach to verifying properties of infinite-state systems. In practice, most previous work on abstract model checking is either restricted to verifying universal properties, or develops special techniques for temporal logics such as modal transition systems or other dual transition systems. By contrast we apply completely standard techniques for constructing abstract interpretations to the abstraction of a CTL semantic function, without restricting the kind of properties that can be verified. Furthermore we show that this leads directly to implementation of abstract model checking algorithms for abstract domains based on constraints, making use of an SMT solver.
The interest in extensions of the logic programming paradigm beyond the class of normal logic programs is motivated by the need of an adequate representation and processing of knowledge. One of the most difficult problems in this area is to find an adequate declarative semantics for logic programs. In the present paper a general preference criterion is proposed that selects the ‘intended’ partial models of generalized logic programs which is a conservative extension of the stationary semantics for normal logic programs of [Prz91]. The presented preference criterion defines a partial model of a generalized logic program as intended if it is generated by a stationary chain. It turns out that the stationary generated models coincide with the stationary models on the class of normal logic programs. The general wellfounded semantics of such a program is defined as the set-theoretical intersection of its stationary generated models. For normal logic programs the general wellfounded semantics equals the wellfounded semantics.
We propose a paraconsistent declarative semantics of possibly inconsistent generalized logic programs which allows for arbitrary formulas in the body and in the head of a rule (i.e. does not depend on the presence of any specific connective, such as negation(-as-failure), nor on any specific syntax of rules). For consistent generalized logic programs this semantics coincides with the stable generated models introduced in [HW97], and for normal logic programs it yields the stable models in the sense of [GL88].
We present the tool Kato which is, to the best of our knowledge, the first tool for plagiarism detection that is directly tailored for answer-set programming (ASP). Kato aims at finding similarities between (segments of) logic programs to help detecting cases of plagiarism. Currently, the tool is realised for DLV programs but it is designed to handle various logic-programming syntax versions. We review basic features and the underlying methodology of the tool.
In this paper we consider a simple syntactic extension of Answer Set Programming (ASP) for dealing with (nested) existential quantifiers and double negation in the rule bodies, in a close way to the recent proposal RASPL-1. The semantics for this extension just resorts to Equilibrium Logic (or, equivalently, to the General Theory of Stable Models), which provides a logic-programming interpretation for any arbitrary theory in the syntax of Predicate Calculus. We present a translation of this syntactic class into standard logic programs with variables (either disjunctive or normal, depending on the input rule heads), as those allowed by current ASP solvers. The translation relies on the introduction of auxiliary predicates and the main result shows that it preserves strong equivalence modulo the original signature.
We introduce a simple approach extending the input language of Answer Set Programming (ASP) systems by multi-valued propositions. Our approach is implemented as a (prototypical) preprocessor translating logic programs with multi-valued propositions into logic programs with Boolean propositions only. Our translation is modular and heavily benefits from the expressive input language of ASP. The resulting approach, along with its implementation, allows for solving interesting constraint satisfaction problems in ASP, showing a good performance.
A wide range of additional forward chaining applications could be realized with deductive databases, if their rule formalism, their immediate consequence operator, and their fixpoint iteration process would be more flexible. Deductive databases normally represent knowledge using stratified Datalog programs with default negation. But many practical applications of forward chaining require an extensible set of user–defined built–in predicates. Moreover, they often need function symbols for building complex data structures, and the stratified fixpoint iteration has to be extended by aggregation operations. We present an new language Datalog*, which extends Datalog by stratified meta–predicates (including default negation), function symbols, and user–defined built–in predicates, which are implemented and evaluated top–down in Prolog. All predicates are subject to the same backtracking mechanism. The bottom–up fixpoint iteration can aggregate the derived facts after each iteration based on user–defined Prolog predicates.
We describe a framework to support the implementation of web-based systems to manipulate data stored in relational databases. Since the conceptual model of a relational database is often specified as an entity-relationship (ER) model, we propose to use the ER model to generate a complete implementation in the declarative programming language Curry. This implementation contains operations to create and manipulate entities of the data model, supports authentication, authorization, session handling, and the composition of individual operations to user processes. Furthermore and most important, the implementation ensures the consistency of the database w.r.t. the data dependencies specified in the ER model, i.e., updates initiated by the user cannot lead to an inconsistent state of the database. In order to generate a high-level declarative implementation that can be easily adapted to individual customer requirements, the framework exploits previous works on declarative database programming and web user interface construction in Curry.
In this talk, I would like to share my experiences gained from participating in four CSP solver competitions and the second ASP solver competition. In particular, I’ll talk about how various programming techniques can make huge differences in solving some of the benchmark problems used in the competitions. These techniques include global constraints, table constraints, and problem-specific propagators and labeling strategies for selecting variables and values. I’ll present these techniques with experimental results from B-Prolog and other CLP(FD) systems.
The genome can be considered the blueprint for an organism. Composed of DNA, it harbours all organism-specific instructions for the synthesis of all structural components and their associated functions. The role of carriers of actual molecular structure and functions was believed to be exclusively assumed by proteins encoded in particular segments of the genome, the genes. In the process of converting the information stored genes into functional proteins, RNA – a third major molecule class – was discovered early on to act a messenger by copying the genomic information and relaying it to the protein-synthesizing machinery. Furthermore, RNA molecules were identified to assist in the assembly of amino acids into native proteins. For a long time, these - rather passive - roles were thought to be the sole purpose of RNA. However, in recent years, new discoveries have led to a radical revision of this view. First, RNA molecules with catalytic functions - thought to be the exclusive domain of proteins - were discovered. Then, scientists realized that much more of the genomic sequence is transcribed into RNA molecules than there are proteins in cells begging the question what the function of all these molecules are. Furthermore, very short and altogether new types of RNA molecules seemingly playing a critical role in orchestrating cellular processes were discovered. Thus, RNA has become a central research topic in molecular biology, even to the extent that some researcher dub cells as “RNA machines”. This thesis aims to contribute towards our understanding of RNA-related phenomena by applying Bioinformatics means. First, we performed a genome-wide screen to identify sites at which the chemical composition of DNA (the genotype) critically influences phenotypic traits (the phenotype) of the model plant Arabidopsis thaliana. Whole genome hybridisation arrays were used and an informatics strategy developed, to identify polymorphic sites from hybridisation to genomic DNA. Following this approach, not only were genotype-phenotype associations discovered across the entire Arabidopsis genome, but also regions not currently known to encode proteins, thus representing candidate sites for novel RNA functional molecules. By statistically associating them with phenotypic traits, clues as to their particular functions were obtained. Furthermore, these candidate regions were subjected to a novel RNA-function classification prediction method developed as part of this thesis. While determining the chemical structure (the sequence) of candidate RNA molecules is relatively straightforward, the elucidation of its structure-function relationship is much more challenging. Towards this end, we devised and implemented a novel algorithmic approach to predict the structural and, thereby, functional class of RNA molecules. In this algorithm, the concept of treating RNA molecule structures as graphs was introduced. We demonstrate that this abstraction of the actual structure leads to meaningful results that may greatly assist in the characterization of novel RNA molecules. Furthermore, by using graph-theoretic properties as descriptors of structure, we indentified particular structural features of RNA molecules that may determine their function, thus providing new insights into the structure-function relationships of RNA. The method (termed Grapple) has been made available to the scientific community as a web-based service. RNA has taken centre stage in molecular biology research and novel discoveries can be expected to further solidify the central role of RNA in the origin and support of life on earth. As illustrated by this thesis, Bioinformatics methods will continue to play an essential role in these discoveries.
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.
Preface
(2010)
The workshops on (constraint) logic programming (WLP) are the annual meeting of the Society of Logic Programming (GLP e.V.) and bring together researchers interested in logic programming, constraint programming, and related areas like databases, artificial intelligence and operations research. In this decade, previous workshops took place in Dresden (2008), Würzburg (2007), Vienna (2006), Ulm (2005), Potsdam (2004), Dresden (2002), Kiel (2001), and Würzburg (2000). Contributions to workshops deal with all theoretical, experimental, and application aspects of constraint programming (CP) and logic programming (LP), including foundations of constraint/ logic programming. Some of the special topics are constraint solving and optimization, extensions of functional logic programming, deductive databases, data mining, nonmonotonic reasoning, , interaction of CP/LP with other formalisms like agents, XML, JAVA, program analysis, program transformation, program verification, meta programming, parallelism and concurrency, answer set programming, implementation and software techniques (e.g., types, modularity, design patterns), applications (e.g., in production, environment, education, internet), constraint/logic programming for semantic web systems and applications, reasoning on the semantic web, data modelling for the web, semistructured data, and web query languages.
The workshops on (constraint) logic programming (WLP) are the annual meeting of the Society of Logic Programming (GLP e.V.) and bring together researchers interested in logic programming, constraint programming, and related areas like databases, artificial intelligence and operations research. The 23rd WLP was held in Potsdam at September 15 – 16, 2009. The topics of the presentations of WLP2009 were grouped into the major areas: Databases, Answer Set Programming, Theory and Practice of Logic Programming as well as Constraints and Constraint Handling Rules.
Die vorliegende Untersuchung zeigt das ständige Wachstum der Dimension und Bedeutung der staatlichen Schutzpflichten als eine eigenständige Funktion der Grundrechte. Mit jedem Fortschritt und der Entwicklung in der modernen Welt, entstehen in der Gesellschaft immer wieder neue Bereiche, die gesetzlicher Regulierung bedürfen. Daher ist die staatliche Aufgabe eindeutig: Der Staat muss die in der Verfassung ausgelegten Prinzipien in der Realität durch die Gesetze umsetzen und sie ständig wiederkehrend nachbessern. Daher ist der Staat gefordert, die Einzelnen repressiv und präventiv zu schützen. Die Dissertation untersucht die Problematik von staatlichen Schutzpflichten im Rahmen der Grundrechte der georgischen Verfassung vom 24. August 1995 im Vergleich mit den Menschenrechten und Grundfreiheiten der Europäischen Menschenrechtskonvention. Die Arbeit greift ein Grundrechtsproblem auf, das sich gerade in rechtlichen und politischen Umbruchssituationen wie diejenige, die Georgien als Nachfolgestaat der zerbrochenen Sowjetunion durchlebt, als besonders wichtig erweist. Auf dem Weg zur dogmatischen Entfaltung einer grundrechtlichen Schutzpflicht wird als eine Art Leitbild die Europäische Menschenrechtskonvention (EMRK) herangezogen. Dies erklärt sich aus der Natur der EMRK, die sich als eine Art Verfassung für Europa darstellt und in Georgien seit 1999 in Kraft ist. In der Arbeit wird auf die deutsche Schutzpflichtenlehre verwiesen. Das erklärt sich aus der in Deutschland schon seit etwa 30 Jahren geführten Diskussion, die immer noch nicht abgeschlossen ist, aber aus der sich bemerkenswerte und kontroverse Ergebnisse ziehen lassen. Die Arbeit zeigt, dass die georgische Verfassung zahlreiche Ansätze der staatlichen Schutzpflichten – allgemeiner und konkreter Art – liefert, die auch vor allem in der Rechtsprechung des Georgischen Verfassungsgerichts verschiedentlich schon aufgegriffen wurden, durchaus zum Teil unter Rückgriff auf Aussagen der Europäischen Menschenrechtskonvention (EMRK) bzw. des Europäischen Gerichtshofes für Menschenrechte (EGMR). Den Bereich der grundrechtlichen Schutzpflichten der georgischen Verfassung auszuleuchten ist für eine relativ neue Rechtstaatlichkeit eines postsowjetischen Staates wichtig, um den Anstoß für eine dringend nötige Debatte zu geben.
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.
Aspect-oriented middleware is a promising technology for the realisation of dynamic reconfiguration in heterogeneous distributed systems. However, like other dynamic reconfiguration approaches, AO-middleware-based reconfiguration requires that the consistency of the system is maintained across reconfigurations. AO-middleware-based reconfiguration is an ongoing research topic and several consistency approaches have been proposed. However, most of these approaches tend to be targeted at specific contexts, whereas for distributed systems it is crucial to cover a wide range of operating conditions. In this paper we propose an approach that offers distributed, dynamic reconfiguration in a consistent manner, and features a flexible framework-based consistency management approach to cover a wide range of operating conditions. We evaluate our approach by investigating the configurability and transparency of our approach and also quantify the performance overheads of the associated consistency mechanisms.
Enforcing security policies to distributed systems is difficult, in particular, when a system contains untrusted components. We designed AspectKE*, a distributed AOP language based on a tuple space, to tackle this issue. In AspectKE*, aspects can enforce access control policies that depend on future behavior of running processes. One of the key language features is the predicates and functions that extract results of static program analysis, which are useful for defining security aspects that have to know about future behavior of a program. AspectKE* also provides a novel variable binding mechanism for pointcuts, so that pointcuts can uniformly specify join points based on both static and dynamic information about the program. Our implementation strategy performs fundamental static analysis at load-time, so as to retain runtime overheads minimal. We implemented a compiler for AspectKE*, and demonstrate usefulness of AspectKE* through a security aspect for a distributed chat system.
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.
Das Ende der Theokratie?
(2010)
Iran steht vor einer neuen Revolution. Die Wahlen und deren offensichtlicher Betrug haben die Spaltung des Landes zu Tage gefördert. Die theokratische Herrschaft kann sich nur noch durch einen ölgeförderten Klientelismus am Leben erhalten und steht nun dort, wo der Schah vor dreißig Jahren gestanden hat. Nur durch eine kluge Politik, die auch Versöhnung bietet, kann ein friedlicher Machtwechsel herbeigeführt und die Demokratisierung des Landes ermöglicht werden.
Die Frage, ob die CDU-Bundestagsabgeordnete Erika Steinbach, seit 1998 Präsidenten des Bundes der Vertriebenen (BdV), einen Sitz im Stiftungsrat des "Zentrums gegen Vertreibung" einnehmen soll, spaltet die politische Landschaft. Die von der SPD beantragte Aktuelle Stunde des Bundestages am 26. November 2009 machte dies erneut deutlich. Auch die neue Bundesregierung ist in dieser Frage gespalten.
Die faulige Luft aus dem tiefsten Mittelalter, denken sich zivilisierte Mitteleuropabewohnende, und sind erstaunt zu erfahren, dass es im Iran heute legal ist, sich von einer Frau in einen Mann umoperieren zu lassen, oder umgekehrt. Noch besser: Die Geschlechtsumwandlung wird von der Krankenkasse bezahlt.
Die zehnten Präsidentschaftswahlen im Iran sorgten für einen Eklat. Ausgerechnet im Jubiläumsjahr, in dem man sich mit Stolz präsentieren wollte, erlebt die Islamische Republik ihren größten Legitimitätsverlust. Mit der Verkündung von Ahmadinedschads Wahlsieg löste das Regime eine Welle der Empörung aus, die bis heute nicht abgeklungen ist. Zwar konnten die Proteste den amtierenden Präsidenten nicht von seiner zweiten Amtszeit abhalten, doch der grüne Sommer hat seine Spuren in der Theokratie hinterlassen.
Brodelnder Iran
(2010)
Die letzten Wahlen im Iran waren die Zündschnur am Pulverfass: Der angestaute Protest entlud sich. Wenig organisiert, jedoch mit Kreativität und erstaunlicher Dauer der Opposition. Zugleich gelingt es dem Regime weiterhin, mit Härte gegen oppositionelle Kräfte vorzugehen. So brodelt es bedrohlich im Iran. Afghanistan bleibt hierzulande auf der Tagesordnung. Obamas "neue Strategie" erinnert an Vietnam. Mit ihr wird sich der Druck auf Berlin verstärken, die Zahl der Soldaten am Hindukusch zu erhöhen. Dies erfordert weiterhin eine Debatte um Alternativen.