Acneiform dermatoses

Acneiform dermatoses are follicular eruptions. The initial lesion is inflammatory, usually a papule or pustule. Comedones are later secondary lesions, a sequel to encapsulation and healing of the primary abscess. The earliest histological event is spongiosis, followed by a break in the follicular epithelium. The spilled follicular contents provokes a nonspecific lymphocytic and neutrophilic infiltrate. Acneiform eruptions are almost always drug induced. Important clues are sudden onset within days, widespread involvement, unusual locations (forearm, buttocks), occurrence beyond acne age, monomorphous lesions, sometimes signs of systemic drug toxicity with fever and malaise, clearing of inflammatory lesions after the drug is stopped, sometimes leaving secondary comedones. Other cutaneous eruptions that may superficially resemble acne vulgaris but that are not thought to be related to it etiologically are due to infection (e.g. gramnegative folliculitis) or unknown causes (e.g. acne necrotica or acne aestivalis)

The communication processor of TUMULT-64

Tumult (Twente University MULTi-processor system) is a modular extendible multi-processor system designed and implemented at the Twente University of Technology in co-operation with Oce Nederland B.V. and the Dr. Neher Laboratories (Dutch PTT). Characteristics of the hardware are: MIMD type, distributed memory, message passing, high performance, real-time and fault tolerant. A distributed real-time operating system has been realized, consisting of a multi-tasking kernel per node, inter process communication via typed messages and a distributed file system. In this paper first a brief description of the system is given, after that the architecture of the communication processor will be discussed. Reduction of the communication overhead due to message passing will be emphasized.\ud \u

Island formation without attractive interactions

We show that adsorbates on surfaces can form islands even if there are no attractive interactions. Instead strong repulsion between adsorbates at short distances can lead to islands, because such islands increase the entropy of the adsorbates that are not part of the islands. We suggest that this mechanism cause the observed island formation in O/Pt(111), but it may be important for many other systems as well.Comment: 11 pages, 4 figure

Real Time in a Real Operating System

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Flexible Scheduling in Multimedia Kernels: an Overview

Current Hard Real-Time (HRT) kernels have their timely behaviour guaranteed on the cost of a rather restrictive use of the available resources. This makes current HRT scheduling techniques inadequate for use in a multimedia environment where we can make a considerable profit by a better and more flexible use of the resources. We will show that we can improve the flexibility and efficiency of multimedia kernels. Therefore we introduce Real Time Transactions (RTT) with Deadline Inheritance policies for a small class of scheduling algorithms and we will evaluate these algorithms for use in a multimedia environmen

Verifying the distributed real-time network protocol RTnet using Uppaal

RTnet is a distributed real-time network protocol for fully-connected local area networks with a broadcast capability. It supports streaming real-time and non-realtime traffic and on-the-fly addition and removal of network nodes. This paper presents a formal analysis of RTnet using the model checker Uppaal. Besides normal protocol behaviour, the analysis focuses on the fault-handling properties of RTnet, in particular recovery after packet loss. Both qualitative and quantitative properties are presented, together with the verification results and conclusions about the robustness of RTnet

Scheduling of Early Quantum Tasks

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

Throughput of Streaming Applications Running on a Multiprocessor Architecture

We study the timing behaviour of streaming applications running on a multiprocessor architecture. Dependencies are derived between the application throughput and the timing characteristics of the processors and communication. Four different processor organizations that strongly influenced the results are considered and compared