Flexible Unterstützung kooperativer Entwurfsumgebungen durch einen Transaktions-Baukasten

Entwurfsumgebungen stellen besondere Anforderungen an das Transaktionsmanagement, so z.B. bei der Realisierung von Kooperations- und Recoverymechanismen. Hierbei ergibt sich ein Zielkonflikt: Einerseits soll das System größtmögliche Sicherheit garantieren, andererseits sollen Flexibilität und Freiheit der Entwickler nicht eingeschränkt werden. Dieser Konflikt kann durch konfigurierbare Systeme gelöst werden, die die Definition unterschiedlicher Typen von Transaktionen und damit die Anpassung an die Anforderungen der jeweiligen Umgebung erlauben. In diesem Papier werden auf der Basis eines Baukasten-Konzeptes Mechanismen zur Unterstützung von Kooperation und Recovery für Entwurfstransaktionen vorgestellt. Der zentrale Gedanke ist, daß Transaktionen bestimmte Rechte erwerben können und die Vergabe dieser Rechte durch Protokolle kontrolliert wird

Controlling cooperation and recovery in nested transactions

Recovery is a hard problem in environments where transactions perform work in a cooperative style (e.g., design environments). We propose concepts to control cooperation and recovery within nested transaction hierarchies. By allowing different nodes to run different protocols, we can build so-called recovery spheres with well-defined properties. We characterize those properties and illustrate them by examples from design environments.<br/

Post-2020 climate agreements in the major economies assessed in the light of global models

Integrated assessment models can help in quantifying the implications of international climate agreements and regional climate action. This paper reviews scenario results from model intercomparison projects to explore different possible outcomes of post-2020 climate negotiations, recently announced pledges and their relation to the 2 °C target. We provide key information for all the major economies, such as the year of emission peaking, regional carbon budgets and emissions allowances. We highlight the distributional consequences of climate policies, and discuss the role of carbon markets for financing clean energy investments, and achieving efficiency and equity

Optical genome mapping identifies a homozygous deletion in the non-coding region of the SCN9A gene in individuals from the same family with congenital insensitivity to pain

We report an index patient with complete insensitivity to pain and a history of painless fractures, joint hypermobility, and behavioral problems. The index patient descends from a family with notable cases among his maternal relatives, including his aunt and his mother’s first cousin, both of whom suffer from congenital insensitivity to pain. The patient had normal results for prior genetic testing: fragile-X syndrome testing, chromosomal microarray analysis, and exome sequencing. Optical genome mapping detected a homozygous deletion affecting the noncoding 5′ untranslated region (UTR) and the first non-coding exon of the SCN9A gene in all affected family members, compatible with recessive disease transmission. Pathogenic homozygous loss-of-function variants in the SCN9A gene are associated with impaired pain sensation in humans. Optical genome mapping can thus detect pathogenic structural variants in patients without molecular etiology by standard diagnostic procedures and is a more accessible diagnostic tool than short-read or long-read whole-genome sequencing

A Locking Algorithm with Premature Unlocks

Standard locking protocols exhibit superior performance than other families of concurrency control mechanisms under a wide range of database (DB) workloads and system configurations. Nevertheless, they have some drawbacks such as unnecessary waiting, which cause an unacceptable behaviour particularly in environments where long transactions (long TAs (LTAs)) are present. In this paper a locking algorithm is presented, which offers the possibility to release data items just after TAs have finished using them. This way waiting times can be significantly reduced. Nevertheless serializability can still be guaranteed. The workload put on the system by the proposed algorithm is not higher than in the traditional 2-Phase-Locking protocol with Wait-For-Graph deadlock detection thus demonstrating the applicability of the algorithm. 1 Introduction Standard locking protocols are the most popular and applied concurrency control algorithms. They are well understood and exhibit superior performance ..

A Formal Foundation Of The Semantics Of Complex Events In Active Database Management Systems

Active database management systems have been developed for applications requiring an automatic reaction in response to certain events. Events can be simple in nature or complex. Complex events consist of simpler ones. Their semantics is usually described with the help of operators on an event algebra. There are quit

Controlling Cooperation and Recovery in Nested Transactions

Recovery is a hard problem in environments where transactions perform work in a cooperative style (e.g., design environments). We propose concepts to control cooperation and recovery within nested transaction hierarchies. By allowing different nodes to run different protocols, we can build so-called recovery spheres with well-defined properties. We characterize those properties and illustrate them by examples from design environments

Parlamentarische Kontrolle, Bundeswehr und oeffentliche Meinung dargestellt am Beispiel der grossen und kleinen Anfragen des Deutschen Bundestages 1953 bis 1987

SIGLEUuStB Koeln(38)-890106591 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

A General Model for Event Specification in Active Database Management Systems

Active database systems have been developed for applications that need an automatic reaction in response to certain conditions being satisfied or certain events occurring. Events can be simple in nature or complex. Complex events can be built from simpler ones with the help of event operators of an event algebra. While numerous papers propose extensions of the set of event operators only very few address the foundations of the semantics of complex events. For this reason most proposals mix different concepts (aspects) of complex events and offer event operators as the only means to control their semantics. This leads to peculiarities as aspects are not handled uniformly by operators and have other semantics than expected or operators of different algebras which, on the first glance, look the same may have different semantics. We have developed a formal meta model for complex events. It splits up the semantics of complex events into elementary, essentially independent dimensions. The re..

Rolling Back in a Selective Way -- An Approach to Recovery for Interactive and Long-Running Transactions

Interactive and long-running transactions are an important concept in non-standard database applications like, e.g., design environments. The main aspect of this paper is recovery for such kinds of transactions. We discuss concepts presented in literature and show why the solutions are not sufficient. We then introduce our approach, called selective recovery. Selective recovery at first considers only that part of work that is directly affected by the failure. In order to guarantee consistency, it is be checked in a second step if further work is indirectly affected and therefore must be invalidated, too. This is done by considering the operations performed on objects and the relationships between objects. Our approach relies on object-oriented database systems