10 research outputs found
Combating state explosion in the detection of dynamic properties of distributed computations
In the context of asynchronous distributed systems, many important applications depend on the ability to check that all observations of the execution of a distributed program, or distributed computation, satisfy a desired (or undesired) temporal evolution of states, or dynamic property. Examples include the implementation of distributed algorithms, automated testing via oracles, debugging, and building fault-tolerant applications through exception detection and handling. When a distributed program exhibits a high degree of concurrency, the number of possible observations of an execution can grow exponentially, quickly leading to an explosion in the amount of space and time required to check a dynamic property. In the worst case, detection of such properties may be defeated. This is the run-time counterpart of the well-known state explosion problem studied in model checking. In this thesis, we study the problem of state explosion as it arises in the detection of dynamic properties. In particular, we consider the potential of applying well-known techniques for dealing with state explosion from model checking to the case of dynamic property detection. Significant semantic similarities between the two problems means that there is great potential for deriving techniques for dealing with state explosion in dynamic property detection based on existing model checking techniques. However, differences between the contexts in which model checking and dynamic property detection take place mean that not all approaches to dealing with state explosion in model checking may carryover to the run-time case. We investigate these similarities and differences and provide the development and analysis of two approaches for combating state explosion in dynamic property detection based on model checking methods: on-the-fly automata theoretic model checking, and partial order reduction.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Object Groups For Groupware Applications: Application Requirements and Design Issues
We consider object groups as the basis of an architecture for structuring real-time groupware applications. We first examine the requirements which distributed, object-oriented groupware applications place on the application designer, and then discuss the design issues for object groups arising from these groupware application requirements. 1 Introduction Groupware is software designed to allow groups of people to use computers to work together closely to achieve a common task. Groupware encompasses application classes such as shared document editors, multi-user virtual reality applications, teleconferencing systems, hypertext document management systems, and collaborative design tools. Real-time groupware applications have the following characteristics [Ellis91]: Distributed. In general, the participants of a groupware session will not be connected to the same machine, and, although they may each be using machines connected by the same local or wide area network, may be in different..
Telescoped Process to Manufacture 6,6,6-Trifluorofucose via Diastereoselective Transfer Hydrogenation: Scalable Access to an Inhibitor of Fucosylation Utilized in Monoclonal Antibody Production
IgG1
monoclonal antibodies with reduced glycan fucosylation have
been shown to improve antibody-dependent cellular cytotoxicity (ADCC)
by allowing more effective binding of the Fc region of these proteins
to T cells receptors. Increased in vivo efficacy in animal models
and oncology clinical trials has been associated with the enhanced
ADCC provided by these engineered mAbs. 6,6,6-Trifluorofucose (<b>1</b>) is a new inhibitor of fucosylation that has been demonstrated
to allow the preparation of IgG1 monoclonal antibodies with lower
fucosylation levels and thus improve the ADCC of these proteins. A
new process has been developed to support the preparation of <b>1</b> on large-scale for wide mAb manufacture applications. The
target fucosylation inhibitor (<b>1</b>) was synthesized from
readily available d-arabinose in 11% overall yield and >99.5/0.5
dr (diastereomeric ratio). The heavily telescoped process includes
seven steps, two crystallizations as purification handles, and no
chromatography. The key transformation of the sequence involves the
diastereoselective preparation of the desired trifluoromethyl-bearing
alcohol in >9/1 dr from a trimethylsilylketal intermediate via
a ruthenium-catalyzed
tandem ketal hydrolysisâtransfer hydrogenation process