Early quantum task scheduling

An Early Quantum Task (EQT) is a Quantum EDF task that has shrunk its first period into one quantum time slot. Its purpose is to be executed as soon as possible, without causing deadline overflow of other tasks. We will derive the conditions under which an EQT can be admitted and can have an immediate start. The advantage of scheduling EQTs is shown by its use in a buffered multi-media server. The EQT is associated with a multimedia stream and it will use its first invocation to fill the buffer, such that a client can start receiving data immediately

Object Distribution Networks for World-wide Document Circulation

This paper presents an Object Distribution System (ODS), a distributed system inspired by the ultra-large scale distribution models used in everyday life (e.g. food or newspapers distribution chains). Beyond traditional mechanisms of approaching information to readers (e.g. caching and mirroring), this system enables the publication, classification and subscription to volumes of objects (e.g. documents, events). Authors submit their contents to publication agents. Classification authorities provide classification schemes to classify objects. Readers subscribe to topics or authors, and retrieve contents from their local delivery agent (like a kiosk or library, with local copies of objects). Object distribution is an independent process where objects circulate asynchronously among distribution agents. ODS is designed to perform specially well in an increasingly populated, widespread and complex Internet jungle, using weak consistency replication by object distribution, asynchronous replication, and local access to objects by clients. ODS is based on two independent virtual networks, one dedicated to the distribution (replication) of objects and the other to calculate optimised distribution chains to be applied by the first network

A New Large-Scale Distributed System

We introduce in this work Object Distribution System, a distributed system based on distribution models used in everyday life (e.g. food distribution chains, newspapers, etc.). This system is designed to scale correctly in a wide area network, using weak consistency replication mechanisms. It is formed by two independent virtual networks on top of Internet, one for replicating objects and the other one to build distribution chains to be used by the first network. As in Internet some sites often become inaccessible due to latency, partitions and flashcrowd, objects in our system are accessed locally and updated off-line. It also provides methods for the classification of objects. This allows selective distribution, and provides order in the chaos that reigns nowadays in Internet. Distribution chains are build dynamically to provide end users with the objects they want to consume, while making good use of available resources. 1. Introduction In the last few years Internet has been grow..

Vertical System Functions

A number of different system concepts have become apparent in the broader context of embedded systems over the past few years. Whilst there are some differences between these, this book argues that in fact there is much they share in common, particularly the important notions of control, heterogenity, wireless communication, dynamics/ad hoc nature and cost.\ud \ud The first part of the book covers cooperating object applications and the currently available application scenarios, such as control and automation, healthcare, and security and surveillance. The second part discusses paradigms for algorithms and interactions. The third part covers various types of vertical system functions, including data aggregation, resource management and time synchronization. The fourth part outlines system architecture and programming models, outlining all currently available architectural models and middleware approaches that can be used to abstract the complexity of cooperating object technology.\ud \ud Finally, the book concludes with a discussion of the trends guiding current research and gives suggestions as to possible future developments and how various shortcomings in the technology can be overcome

Synthesis and Evaluation of a Library of Alternating Amphipathic Copolymers to Solubilize and Study Membrane Proteins

Amphipathic copolymers such as poly(styrene-maleic acid) (SMA) are promising tools for the facile extraction of membrane proteins (MPs) into native nanodiscs. Here, we designed and synthesized a library of well-defined alternating copolymers of SMA analogues in order to elucidate polymer properties that are important for MP solubilization and stability. MP extraction efficiency was determined using KcsA from E.coli membranes and general solubilization efficiency was investigated via turbidimetry experiments on membranes of E.coli, yeast mitochondria and synthetic lipids. Remarkably, halogenation of SMA copolymers dramatically improved solubilization efficiency in all systems, while substituents on the copolymer backbone improved resistance to Ca2+. Relevant polymer properties were found to include hydrophobic balance, size and positioning of substituents, rigidity and electronic effects. The library thus contributes to the rational design of copolymers for the study of MPs