980,699 research outputs found

    LTAG semantics for questions

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    This papers presents a compositional semantic analysis of interrogatives clauses in LTAG (Lexicalized Tree Adjoining Grammar) that captures the scopal properties of wh- and nonwh-quantificational elements. It is shown that the present approach derives the correct semantics for examples claimed to be problematic for LTAG semantic approaches based on the derivation tree. The paper further provides an LTAG semantics for embedded interrogatives

    The removal of thermally aged films of triacylglycerides by surfactant solutions

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    Thermal ageing of triacylglycerides (TAG) at high temperatures produces films which resist removal using aqueous surfactant solutions. We used a mass loss method to investigate the removal of thermally aged TAG films from hard surfaces using aqueous solutions of surfactants of different charge types. It was found that cationic surfactants are most effective at high pH, whereas anionics are most effective at low pH and a non-ionic surfactant is most effective at intermediate pH. We showed that the TAG film removal process occurs in several stages. In the first ‘‘lag phase’’ no TAG removal occurs; the surfactant first partitions into the thermally aged film. In the second stage, the TAG film containing surfactant was removed by solubilisation into micelles in the aqueous solution. The effects of pH and surfactant charge on the TAG removal process correlate with the effects of these variables on the extent of surfactant partitioning to the TAG film and on the maximum extent of TAG solubilisation within the micelles. Additionally, we showed how the TAG removal is enhanced by the addition of amphiphilic additives such as alcohols which act as co-surfactants. The study demonstrates that aqueous surfactant solutions provide a viable and more benign alternative to current methods for the removal of thermally aged TAG films

    Evaluating tag-based information access in image collections

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    The availability of social tags has greatly enhanced access to information. Tag clouds have emerged as a new "social" way to find and visualize information, providing both one-click access to information and a snapshot of the "aboutness" of a tagged collection. A range of research projects explored and compared different tag artifacts for information access ranging from regular tag clouds to tag hierarchies. At the same time, there is a lack of user studies that compare the effectiveness of different types of tag-based browsing interfaces from the users point of view. This paper contributes to the research on tag-based information access by presenting a controlled user study that compared three types of tag-based interfaces on two recognized types of search tasks - lookup and exploratory search. Our results demonstrate that tag-based browsing interfaces significantly outperform traditional search interfaces in both performance and user satisfaction. At the same time, the differences between the two types of tag-based browsing interfaces explored in our study are not as clear. Copyright 2012 ACM

    Path-factors involving paths of order seven and nine

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    In this paper, we show the following two theorems (here ci(GX)c_{i}(G-X) is the number of components CC of GXG-X with V(C)=i|V(C)|=i): (i)~If a graph GG satisfies c1(GX)+13c3(GX)+13c5(GX)23Xc_{1}(G-X)+\frac{1}{3}c_{3}(G-X)+\frac{1}{3}c_{5}(G-X)\leq \frac{2}{3}|X| for all XV(G)X\subseteq V(G), then GG has a {P2,P7}\{P_{2},P_{7}\}-factor. (ii)~If a graph GG satisfies c1(GX)+c3(GX)+23c5(GX)+13c7(GX)23Xc_{1}(G-X)+c_{3}(G-X)+\frac{2}{3}c_{5}(G-X)+\frac{1}{3}c_{7}(G-X)\leq \frac{2}{3}|X| for all XV(G)X\subseteq V(G), then GG has a {P2,P9}\{P_{2},P_{9}\}-factor.Comment: 29 pages, 4 figure

    Tree-local MCTAG with shared nodes : an analysis of word order variation in German and Korean

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    Tree Adjoining Grammars (TAG) are known not to be powerful enough to deal with scrambling in free word order languages. The TAG-variants proposed so far in order to account for scrambling are not entirely satisfying. Therefore, an alternative extension of TAG is introduced based on the notion of node sharing. Considering data from German and Korean, it is shown that this TAG-extension can adequately analyse scrambling data, also in combination with extraposition and topicalization.Les Grammaires dArbres Adjoints (TAG) sont connues pour ne pas etre assez puissantes pour traiter le brouillage darguments dans des langues à ordre desmots libre. Les variantes TAG proposées jusqu´à maintenant pour expliquer le brouillage ne sont pas entièrement satisfaisantes. Nous présentons ici une extension alternative de TAG, basée sur la notion du partage de noeuds. En considerant des données de lallemand et du coréen, on montre que cette extension de TAG peut en juste proportion analyser des données de brouillage d’arguments, également en combinaison avec lextraposition et la topicalisation

    On a Vizing-type integer domination conjecture

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    Given a simple graph GG, a dominating set in GG is a set of vertices SS such that every vertex not in SS has a neighbor in SS. Denote the domination number, which is the size of any minimum dominating set of GG, by γ(G)\gamma(G). For any integer k1k\ge 1, a function f:V(G){0,1,...,k}f : V (G) \rightarrow \{0, 1, . . ., k\} is called a \emph{{k}\{k\}-dominating function} if the sum of its function values over any closed neighborhood is at least kk. The weight of a {k}\{k\}-dominating function is the sum of its values over all the vertices. The {k}\{k\}-domination number of GG, γ{k}(G)\gamma_{\{k\}}(G), is defined to be the minimum weight taken over all {k}\{k\}-domination functions. Bre\v{s}ar, Henning, and Klav\v{z}ar (On integer domination in graphs and Vizing-like problems. \emph{Taiwanese J. Math.} {10(5)} (2006) pp. 1317--1328) asked whether there exists an integer k2k\ge 2 so that γ{k}(GH)γ(G)γ(H)\gamma_{\{k\}}(G\square H)\ge \gamma(G)\gamma(H). In this note we use the Roman {2}\{2\}-domination number, γR2\gamma_{R2} of Chellali, Haynes, Hedetniemi, and McRae, (Roman {2}\{2\}-domination. \emph{Discrete Applied Mathematics} {204} (2016) pp. 22-28.) to prove that if GG is a claw-free graph and HH is an arbitrary graph, then γ{2}(GH)γR2(GH)γ(G)γ(H)\gamma_{\{2\}}(G\square H)\ge \gamma_{R2}(G\square H)\ge \gamma(G)\gamma(H), which also implies the conjecture for all k2k\ge 2.Comment: 8 page
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