1,056 research outputs found

    Control of Towing Kites for Seagoing Vessels

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    In this paper we present the basic features of the flight control of the SkySails towing kite system. After introduction of coordinate definitions and basic system dynamics we introduce a novel model used for controller design and justify its main dynamics with results from system identification based on numerous sea trials. We then present the controller design which we successfully use for operational flights for several years. Finally we explain the generation of dynamical flight patterns.Comment: 12 pages, 18 figures; submitted to IEEE Trans. on Control Systems Technology; revision: Fig. 15 corrected, minor text change

    Learning to Segment Every Thing

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    Most methods for object instance segmentation require all training examples to be labeled with segmentation masks. This requirement makes it expensive to annotate new categories and has restricted instance segmentation models to ~100 well-annotated classes. The goal of this paper is to propose a new partially supervised training paradigm, together with a novel weight transfer function, that enables training instance segmentation models on a large set of categories all of which have box annotations, but only a small fraction of which have mask annotations. These contributions allow us to train Mask R-CNN to detect and segment 3000 visual concepts using box annotations from the Visual Genome dataset and mask annotations from the 80 classes in the COCO dataset. We evaluate our approach in a controlled study on the COCO dataset. This work is a first step towards instance segmentation models that have broad comprehension of the visual world

    Completing Partial Packings of Bipartite Graphs

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    Given a bipartite graph HH and an integer nn, let f(n;H)f(n;H) be the smallest integer such that, any set of edge disjoint copies of HH on nn vertices, can be extended to an HH-design on at most n+f(n;H)n+f(n;H) vertices. We establish tight bounds for the growth of f(n;H)f(n;H) as nn \rightarrow \infty. In particular, we prove the conjecture of F\"uredi and Lehel \cite{FuLe} that f(n;H)=o(n)f(n;H) = o(n). This settles a long-standing open problem

    Drop cost and wavelength optimal two-period grooming with ratio 4

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    We study grooming for two-period optical networks, a variation of the traffic grooming problem for WDM ring networks introduced by Colbourn, Quattrocchi, and Syrotiuk. In the two-period grooming problem, during the first period of time, there is all-to-all uniform traffic among nn nodes, each request using 1/C1/C of the bandwidth; and during the second period, there is all-to-all uniform traffic only among a subset VV of vv nodes, each request now being allowed to use 1/C1/C' of the bandwidth, where C<CC' < C. We determine the minimum drop cost (minimum number of ADMs) for any n,vn,v and C=4 and C{1,2,3}C' \in \{1,2,3\}. To do this, we use tools of graph decompositions. Indeed the two-period grooming problem corresponds to minimizing the total number of vertices in a partition of the edges of the complete graph KnK_n into subgraphs, where each subgraph has at most CC edges and where furthermore it contains at most CC' edges of the complete graph on vv specified vertices. Subject to the condition that the two-period grooming has the least drop cost, the minimum number of wavelengths required is also determined in each case

    strongly balanced 4 kite designs nested into oq systems

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    In this paper we determine the spectrum for octagon quadrangle systems [OQS] which can be partitioned into two strongly balanced 4-kitedesigns

    An Exploration of the Roles Values Play in Design Decision-Making

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    The paper presents the findings of a study into design decision-making and specifically the use of values during design decision-making. It briefly describes the development of a taxonomy of values used in design decision-making developed from a series of pilot interviews, protocol analysis and focus groups. This was necessary because although the values agenda is not new, previous studies were found to have gaps, or did not reflect the current state of play. From this more in-depth case studies were carried out to explore the influence of values in design decision-making. Eight designers were asked to design a lectern out of sustainable materials. They were given one day to complete the project. For one hour during the day they were asked to ‘talk aloud’ while being videoed, also known as concurrent verbalisation and protocol analysis. They also took part in a 40 minute retrospective interview about their design work, at the end of the day. One designer was asked to complete a ten day design project in order to verify the results against a longitudinal project. They also took part in a 40 minute retrospective interview at the end of the project. The paper presents some of the rich data collected during the study. And illustrates the ability to research the role of values in design decision-making. The data generated shows values driving many of the decisions designers make including the way in which they cognitively organise their design activity and through which they can reduce avenues of enquiry. Keywords: Design Decision-Making, Knowledge, Skills, Values, Empirical Evidence, Research Methods</p

    ON THE EMBEDDING OF GROUPS AND DESIGNS IN A DIFFERENCE BLOCK DESIGN

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    A difference BIBD is a balanced incomplete block design on a group which isconstructed by transferring a regular perfect difference system by a subgroup of its point set. There is an obvious bijection between these BIBDs and some copies of their point sets as two sets. In this paper, we investigate the algebraic structure of these block designs by definning a group-isomorphism between them and their point sets. It has done by defning some relations between the independent-graphs of difference BIBDs and some Cayley graphs of their point sets. It is shown that some Cayley graphs are embedded in the independent-graph of difference BIBDs as a spanning sub-graphs. Due to find these relations, we find out a configuration ordering on these BIBDs, also we achieve some results about the classification of these BIBDs. All in this paper are on difference BIBDs with even numbers of the points

    The Spectrum of Balanced P^(3)(1, 5)-Designs

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    Given a 3-uniform hypergraph H(3), an H(3)-decomposition of the complete hypergraph K(3)_v is a collection of hypergraphs, all isomorphic to H(3), whose edge sets partition the edge set of K(3)_v. An H(3)-decomposition of K(3)_v is also called an H(3)-design and the hypergraphs of the partition are said to be the blocks. An H(3)-design is said to be balanced if the number of blocks containing any given vertex of K(3)_v is a constant. In this paper, we determine completely, without exceptions, the spectrum of balanced P(3)(1 5)-designs
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