177,067 research outputs found
Approximating the maximum consecutive subsums of a sequence
No full textWe present a novel approach for computing all maximum consecutive subsums in a sequence of positive integers in near-linear time. Solutions for this problem over binary sequences can be used for reporting existence of Parikh vectors in a bit string. Recently, several attempts have been made to build indexes for all Parikh vectors of a binary string in subquadratic time. However, no algorithm is known to date which can beat by more than a polylogarithmic factor the naive Θ(n2) procedure. We show how to construct a (1+ε)-approximate index for all Parikh vectors of a binary string in O(nlog^2n/log(1+ε), for any constant ε>0.
Such index is approximate, in the sense that it leaves a small chance for false positives (no false negatives are possible). However, we can tune the parameters of the algorithm so that we can strictly control such a chance of error while still guaranteeing strong subquadratic running time
Asymptotic multipartite version of the Alon–Yuster theorem
No full textIn this paper, we prove the asymptotic multipartite version of the Alon–Yuster theorem, which is a generalization of the Hajnal–Szemerédi theorem: If k≥3 is an integer, H is a k -colorable graph and γ>0 is fixed, then, for every sufficiently large n , where |V(H)| divides n, and for every balanced k-partite graph G on kn vertices with each of its corresponding View the MathML source bipartite subgraphs having minimum degree at least (k−1)n/k+γn, G has a subgraph consisting of kn/|V(H)| vertex-disjoint copies of H. The proof uses the Regularity method together with linear programming
A Common Extension of the Erdős–Stone Theorem and the Alon–Yuster Theorem for Unbounded Graphs
No full textAbstractThe Erdős–Stone theorem (1946, Bull. Am. Math. Soc., 52, 1089–1091) and the Alon–Yuster theorem (1992, Graphs Comb., 8, 95–102 ) are both very fundamental in extremal graph theory. We give a common extension of them, which states as follows: For everyϵ> 0 and r≥ 2, there exists c=cϵ, r> 0 such that, for any 0 ≤θ≤ 1, if H is a graph of order | H | ≤clogn and with chromatic number r then every n -vertex graph G with minimum degree at least ( 1 − 1 __ r−1 +θ ____ r(r−1)) n contains at least (θ−ϵ)n/| H | vertex-disjoint copies of H.When θ=ϵr (r− 1) or θ= 1, it would imply the two theorems.The important point is that our theorem enables us to deal with a larger graph H of order | H | →∞(as n→∞), while | H | was fixed in the Alon–Yuster theorem (and in another common extension by Komlós (2000, Combinatorica,20, 203–218)).The bounds clogn and ( 1 − 1 __ r−1 +θ ____r (r−1)) n are both essentially the best possible
Independent transversals in r-partite graphs
No full textAbstractLet G(r,n) denote the set of all r-partite graphs consisting of n vertices in each partite class. An independent transversal of G ∈ G(r,n) is an independent set consisting of exactly one vertex from each vertex class. Let Δ(r,n) be the maximal integer such that every G ∈ G(r,n) with maximal degree less than Δ(r,n) contains an independent transversal. Let Cr = limn→∞ Δ(r,n)/n. We establish the following upper and lower bounds on Cr, provided r > 2: 2⌊log r⌋−12⌊log r⌋−1⩾Cr⩾max{12e, 12⌈log(r3)⌉, 13 · 2⌈log r⌉−3}. For all r > 3, both upper and lower bounds improve upon previously known bounds of Bollobás, Erdős and Szemerédi. In particular, we obtain that C4 = 23, and that limr→∞ Cr ⩾ 1/(2e), where the last bound is a consequence of a lemma of Alon and Spencer. This solves two open problems of Bollobás, Erdős and Szemerédi
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Two problems on cycles in random graphs
No full textWe prove three results. First, an old conjecture of Zs. Tuza says that for any graph G, the ratio of the minimum size, τ3(G), of a set of edges meeting all triangles to the maximum size, ν3(G), of an edge-disjoint triangle packing is at most 2. Disproving a conjecture of R. Yuster [40], we show that for any fixed, positive α there are arbitrarily large graphs G of positive density satisfying τ3(G) > (1 − o(1))|G|/2 and ν3(G) < (1 + α)|G|/4. Second, write C(G) for the cycle space of a graph G, Cκ(G) for the subspace of C(G) spanned by the copies of Cκ in G, Tκ for the class of graphs satisfying Cκ(G) = C(G), and Qκ for the class of graphs each of whose edges lies in a Cκ. We prove that for every odd κ ≥ 3 and G = Gn,p, max p Pr(G ∈ Qκ Tκ) → 0; so the Cκ’s of a random graph span its cycle space as soon as they cover its edges. For κ = 3 this was shown in [12]. Third, we extend the seminal van den Berg–Kesten Inequality [9] on disjoint occurrence of two events to a setting with arbitrarily many events, where the quantity of interest is the maximum number that occur disjointly. This provides a handy tool for bounding upper tail probabilities for event counts in a product probability space.Ph.D.Includes bibliographical referencesby Jacob D. Baro
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Letter from R. R. Zellick, Assistant Trust Officer, Anglo California National Bank of San Francisco, to Joseph R. Goodman, October 2, 1942
No full textLetter from R. R. Zellick, Assistant Trust Officer at The Anglo California National Bank of San Francisco, to Joseph R. Goodman, regarding property owned by Dave Tatsuno. Zellick mentions a dispute between current tenants and Tatsuno, and that Tatsuno has asked Goodman to help locate trustworthy tenants.Personal correspondence, organizational records, government documents, publications, and other papers created or collected by Joseph R. Goodman documenting the forced removal and incarceration of Japanese Americans during World War II, as well as organized resistance to incarceration. Included in the collection are records of the Japanese Young Men's Christian Association and the Japanese American Citizens' League in San Francisco, including papers of the Japanese YMCA's executive secretary Lincoln Kanai; Sakai family papers; Goodman's correspondence to and from Japanese American incarcerees, organizations opposing forced removal and incarceration of Japanese Americans, the War Relocation Authority, and others; publications, photographs, and ephemera from the Topaz Relocation Center, where Goodman taught high school; War Relocation Authority records and publications; and newspaper clippings, pamphlets, and reports about forced removal and incarceration created by various government, religious, and civic organizations, in California and nationwide
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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