Electro-magnetic Tooling for Metal Forming and Powder Compaction

The multipurpose FE Code ANSYS is employed to simulate an electro-magnetic forming process. A complicated compression coil with a ferromagnetic outer screen and a stepped field shaper is considered. Details on FE model building are thoroughly discussed. The calculated parameters are the magnetic flux density around the conductors as well as the Lorentz forces developed in both the field shaper and the workpiece. A simplified analysis of the workpiece deformation characteristics is also provided. An equivalent circuit method is employed in order to validate the results from the electro-magnetic FE model. Results from both analyses are in good agreement, denoting that the FE results are valid from an engineering point of view

The (h,k)-Server Problem on Bounded Depth Trees

We study the k-server problem in the resource augmentation setting, i.e., when the performance of the online algorithm with k servers is compared to the offline optimal solution with h ≤ k servers. The problem is very poorly understood beyond uniform metrics. For this special case, the classic k-server algorithms are roughly (1+1/ϵ)-competitive when k=(1+ϵ) h, for any ϵ > 0. Surprisingly, however, no o(h)-competitive algorithm is known even for HSTs of depth 2 and even whe

Nested convex bodies are chaseable

In the Convex Body Chasing problem, we are given an initial point v0 2 Rd and an online sequence of n convex bodies F1; : : : ; Fn. When we receive Fi, we are required to move inside Fi. Our goal is to minimize the total distance traveled. This fundamental online problem was first studied by Friedman and Linial (DCG 1993). They proved an ( p d) lower bound on the competitive ratio, and conjectured that a competitive ratio depending only on d is possible. However, despite much interest in the problem, the conjecture remains wide open. We consider the setting in which the convex bodies are nested: F1 : : : Fn. The nested setting is closely related to extending the online LP framework of Buchbinder and Naor (ESA 2005) to arbitrary linear constraints. Moreover, this setting retains much of the difficulty of the general setting and captures an essential obstacle in resolving Friedman and Linial's conjecture. In this work, we give a f(d)competitive algorithm for chasing nested convex bodies in Rd

Tight bounds for Double Coverage against weak adversaries

We study the Double Coverage (DC) algorithm for the k-server problem in tree metrics in the (h,k)-setting, i.e., when DC with k servers is compared against an offline optimum algorithm with h ≤ k servers. It is well-known that in such metric spaces DC is k-competitive (and thus optimal) for h = k. We prove that even if k > h the competitive ratio of DC does not improve; in fact, it increases slightly as k grows, tending to h + 1. Specifically, we give matching upper and lower bounds of (k(h+1)) / (k+1) on the competitive ratio of DC on any tree metric

Tight bounds for Double Coverage against weak adversaries

We study the Double Coverage (DC) algorithm for the k-server problem in tree metrics in the (h,k)-setting, i.e., when DC with k servers is compared against an offline optimum algorithm with h \xe2\x89\xa4 k servers. It is well-known that in such metric spaces DC is k-competitive (and thus optimal) for h = k. We prove that even if k > h the competitive ratio of DC does not improve; in fact, it increases slightly as k grows, tending to h + 1. Specifically, we give matching upper and lower bounds of (k(h+1)) / (k+1) on the competitive ratio of DC on any tree metric

A SOA-Based Embedded Systems Development Environment for Industrial Automation

<p>Abstract</p> <p>Currently available toolsets for the development of embedded systems adopt traditional architectural styles and do not cover the whole requirements of the development process, with extensibility being the major drawback. In this paper, a service-oriented architectural framework that exploits semantic web is defined. Features required in the development process are defined as web services and published into the public domain, so as to be used on demand by developers to construct their projects' specific integrated development environments (IDEs). The infrastructure required to build a web service-based IDE is presented. Specific web services are defined and the way these services affect the development process is discussed. Special focus is given on the device model and the means that such a modelling can significantly improve the development process. A prototype implementation demonstrates the applicability and usefulness of the proposed demand-led development process in the industrial automation domain.</p