8 research outputs found
An Optimal Single-Path Routing Algorithm in the Datacenter Network DPillar
DPillar has recently been proposed as a server-centric datacenter network and is combinatorially related to (but distinct from) the well-known wrapped butterfly network. We explain the relationship between DPillar and the wrapped butterfly network before proving that the underlying graph of DPillar is a Cayley graph; hence, the datacenter network DPillar is node-symmetric. We use this symmetry property to establish a single-path routing algorithm for DPillar that computes a shortest path and has time complexity O(k), where k parameterizes the dimension of DPillar (we refer to the number of ports in its switches as n). Our analysis also enables us to calculate the diameter of DPillar exactly. Moreover, our algorithm is trivial to implement, being essentially a conditional clause of numeric tests, and improves significantly upon a routing algorithm earlier employed for DPillar. Furthermore, we provide empirical data in order to demonstrate this improvement. In particular, we empirically show that our routing algorithm improves the average length of paths found, the aggregate bottleneck throughput, and the communication latency. A secondary, yet important, effect of our work is that it emphasises that datacenter networks are amenable to a closer combinatorial scrutiny that can significantly improve their computational efficiency and performance
3D-in-2D Displays for ATC.
This paper reports on the efforts and accomplishments
of the 3D-in-2D Displays for ATC project at the end of Year 1.
We describe the invention of 10 novel 3D/2D visualisations that
were mostly implemented in the Augmented Reality ARToolkit.
These prototype implementations of visualisation and interaction
elements can be viewed on the accompanying video. We have
identified six candidate design concepts which we will further
research and develop. These designs correspond with the early
feasibility studies stage of maturity as defined by the NASA
Technology Readiness Level framework. We developed the
Combination Display Framework from a review of the literature,
and used it for analysing display designs in terms of display
technique used and how they are combined. The insights we
gained from this framework then guided our inventions and the
human-centered innovation process we use to iteratively invent.
Our designs are based on an understanding of user work
practices. We also developed a simple ATC simulator that we
used for rapid experimentation and evaluation of design ideas.
We expect that if this project continues, the effort in Year 2 and 3
will be focus on maturing the concepts and employment in a
operational laboratory settings
Air Traffic Management Abbreviation Compendium
As in all fields of work, an unmanageable number of abbreviations are used today in aviation for terms, definitions, commands, standards and technical descriptions. This applies in general to the areas of aeronautical communication, navigation and surveillance, cockpit and air traffic control working positions, passenger and cargo transport, and all other areas of flight planning, organization and guidance. In addition, many abbreviations are used more than once or have different meanings in different languages.
In order to obtain an overview of the most common abbreviations used in air traffic management, organizations like EUROCONTROL, FAA, DWD and DLR have published lists of abbreviations in the past, which have also been enclosed in this document. In addition, abbreviations from some larger international projects related to aviation have been included to provide users with a directory as complete as possible. This means that the second edition of the Air Traffic Management Abbreviation Compendium includes now around 16,500 abbreviations and acronyms from the field of aviation
An Approximate Dynamic Programming Approach to the Scheduling of Impatient Jobs in a Clearing System.
A single server is faced with a collection of jobs of varying duration and urgency. Before service starts, all jobs are subject to an initial triage, i.e., an assessment of both their urgency and of their service requirement, and are allocated to distinct classes. Jobs in one class have independent and identically distributed lifetimes during which they are available for service. Should a job's lifetime example before its service begins then it is lost from the system unserved. The goal is to schedule the jobs for service to maximise the expected number served to completion. Two heuristic policies have been proposed in the literature. One works well in a "no loss" limit while the other does so when lifetimes are short. Both can exhibit poor performance for problems at some distance from the regimes for which they were designed. We develop a robustly good heuristic by an approximative approach to the application of a single policy improvement step to the first policy above, in which we use a fluid model to obtain an approximation for its value function. The performance of the proposed heuristic is investigated in an extensive numerical study. This problem is substantially complicated if the initial triage is subject to error. We take a Bayesian approach to this additional uncertainty and discuss the design of heuristic policies to maximise the Bayes' return. We identify problem features for which a high price is paid for poor initial triage and for which improvements in initial job assessment yield significant improvements in service outcomes. An analytical upperbound for the cost of imperfect classification is developed for exponentially distributed lifetime cases. An extensive numerical study is conducted to explore the behaviour of the cost in more general situations
Graduate course catalog (Florida International University). [2011-2012]
This catalog contains a description of the various policies, graduate programs, degree requirements, and course offerings at Florida International University during the 2011-2012 academic year.https://digitalcommons.fiu.edu/catalogs/1064/thumbnail.jp
Aspects of coordination chemistry / Frank Richard Keene.
Includes bibliographical references.1 v. :Thesis (D.Sc.) -- University of Adelaide, Dept. of Chemistry, 199