1,058 research outputs found

    Intelligence Agencies, Law Enforcement, and the Prosecution Team

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    In November 1996, a hijacked Ethiopian Airlines jet crash landed in Indian Ocean waters near the Comoro Islands. Among the casualties were several American citizens. Following the collapse of the Soviet Union, rogue states and international terrorist groups commenced efforts, which continue today, to acquire nuclear warheads and fissionable material from the successor nations

    Succinct Partial Sums and Fenwick Trees

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    We consider the well-studied partial sums problem in succint space where one is to maintain an array of n k-bit integers subject to updates such that partial sums queries can be efficiently answered. We present two succint versions of the Fenwick Tree - which is known for its simplicity and practicality. Our results hold in the encoding model where one is allowed to reuse the space from the input data. Our main result is the first that only requires nk + o(n) bits of space while still supporting sum/update in O(log_b n) / O(b log_b n) time where 2 <= b <= log^O(1) n. The second result shows how optimal time for sum/update can be achieved while only slightly increasing the space usage to nk + o(nk) bits. Beyond Fenwick Trees, the results are primarily based on bit-packing and sampling - making them very practical - and they also allow for simple optimal parallelization

    Efficient Dynamic Approximate Distance Oracles for Vertex-Labeled Planar Graphs

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    Let GG be a graph where each vertex is associated with a label. A Vertex-Labeled Approximate Distance Oracle is a data structure that, given a vertex vv and a label λ\lambda, returns a (1+ε)(1+\varepsilon)-approximation of the distance from vv to the closest vertex with label λ\lambda in GG. Such an oracle is dynamic if it also supports label changes. In this paper we present three different dynamic approximate vertex-labeled distance oracles for planar graphs, all with polylogarithmic query and update times, and nearly linear space requirements

    Speeding up shortest path algorithms

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    Given an arbitrary, non-negatively weighted, directed graph G=(V,E)G=(V,E) we present an algorithm that computes all pairs shortest paths in time O(mn+mlgn+nTψ(m,n))\mathcal{O}(m^* n + m \lg n + nT_\psi(m^*, n)), where mm^* is the number of different edges contained in shortest paths and Tψ(m,n)T_\psi(m^*, n) is a running time of an algorithm to solve a single-source shortest path problem (SSSP). This is a substantial improvement over a trivial nn times application of ψ\psi that runs in O(nTψ(m,n))\mathcal{O}(nT_\psi(m,n)). In our algorithm we use ψ\psi as a black box and hence any improvement on ψ\psi results also in improvement of our algorithm. Furthermore, a combination of our method, Johnson's reweighting technique and topological sorting results in an O(mn+mlgn)\mathcal{O}(m^*n + m \lg n) all-pairs shortest path algorithm for arbitrarily-weighted directed acyclic graphs. In addition, we also point out a connection between the complexity of a certain sorting problem defined on shortest paths and SSSP.Comment: 10 page

    The Makings of Creativity and Empathy: Maps of Maternal Representations

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    ABSTRACT The Makings of Creativity and Empathy: Maps of Maternal Representations by Anielle M. Fredman Advisor: Sasha Rudenstine, Ph.D. The present study investigates the relationship between maternal fantasy of the child and their relationship, and children’s unconscious processes. In addition, the study aims to ascertain the link between maternal representations and aspects of the child’s intrapsychic world, including ego functioning, object relations, and processes of separation-individuation. Maternal fantasy was measured in an original way with a tripartite typology of Positive, Mixed-Complex, and Contradictory Representations, applied to the Parent Development Interview-Revised Short (Slade et al., 2004), adapted from the Working Model of the Child Interview (WMCI) (Zeanah et al., 1993). Ego functioning and object relations were captured via children’s Rorschach (RIM) (Rorschach, 1921) transcripts and assessed utilizing Klopfer et al. (1954) scoring, Urist’s (1977) Mutuality of Autonomy scale (MOA), and Coonerty’s Separation-Individuation scale (1986). Results are based on a sample of youth (N = 35, 54% male, 46% female, 26% White, 34% Black, 9% Latinx, 31% multiracial, 68% below median income) ages 5–15, receiving mental health services at a community-based clinic in an under resourced urban population. Outcomes from the present study support the hypothesis that a significant relationship exists between maternal representations and children’s intrapsychic health and functioning. Outcomes revealed significant between-group differences in children’s use of healthy movement scores and object relational health in the mixed-complex maternal representation group, as compared with the positive and contradictory maternal representation group. Broadly, these results suggest differences in youth’s unconscious processes as it relates to maternal representations of the relationship. Furthermore, this study offers an integration of psychoanalytic and attachment-based theory with test data and demonstrates the applicability of maternal representation and youth personality assessment to treatment conceptualization. Keywords: attachment, object relations, maternal fantasy, Rorschac

    Combining All Pairs Shortest Paths and All Pairs Bottleneck Paths Problems

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    We introduce a new problem that combines the well known All Pairs Shortest Paths (APSP) problem and the All Pairs Bottleneck Paths (APBP) problem to compute the shortest paths for all pairs of vertices for all possible flow amounts. We call this new problem the All Pairs Shortest Paths for All Flows (APSP-AF) problem. We firstly solve the APSP-AF problem on directed graphs with unit edge costs and real edge capacities in O~(tn(ω+9)/4)=O~(tn2.843)\tilde{O}(\sqrt{t}n^{(\omega+9)/4}) = \tilde{O}(\sqrt{t}n^{2.843}) time, where nn is the number of vertices, tt is the number of distinct edge capacities (flow amounts) and O(nω)<O(n2.373)O(n^{\omega}) < O(n^{2.373}) is the time taken to multiply two nn-by-nn matrices over a ring. Secondly we extend the problem to graphs with positive integer edge costs and present an algorithm with O~(tc(ω+5)/4n(ω+9)/4)=O~(tc1.843n2.843)\tilde{O}(\sqrt{t}c^{(\omega+5)/4}n^{(\omega+9)/4}) = \tilde{O}(\sqrt{t}c^{1.843}n^{2.843}) worst case time complexity, where cc is the upper bound on edge costs

    Towards Precision Dermatology: Emerging Role of Proteomic Analysis of the Skin

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    Background: The skin is the largest organ in the human body and serves as a multilayered protective shield from the environment as well as a sensor and thermal regulator. However, despite its importance, many details about skin structure and function at the molecular level remain incompletely understood. Recent advances in liquid chromatography tandem mass spectrometry (LC-MS/MS) proteomics have enabled the quantification and characterization of the proteomes of a number of clinical samples, including normal and diseased skin. Summary: Here, we review the current state of the art in proteomic analysis of the skin. We provide a brief overview of the technique and skin sample collection methodologies as well as a number of recent examples to illustrate the utility of this strategy for advancing a broader understanding of the pathology of diseases as well as new therapeutic options. Key Messages: Proteomic studies of healthy skin and skin diseases can identify potential molecular biomarkers for improved diagnosis and patient stratification as well as potential targets for drug development. Collectively, efforts such as the Human Skinatlas offer improved opportunities for enhancing clinical practice and patient outcomes

    Cache-Oblivious Persistence

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    Partial persistence is a general transformation that takes a data structure and allows queries to be executed on any past state of the structure. The cache-oblivious model is the leading model of a modern multi-level memory hierarchy.We present the first general transformation for making cache-oblivious model data structures partially persistent

    Faster algorithms for 1-mappability of a sequence

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    In the k-mappability problem, we are given a string x of length n and integers m and k, and we are asked to count, for each length-m factor y of x, the number of other factors of length m of x that are at Hamming distance at most k from y. We focus here on the version of the problem where k = 1. The fastest known algorithm for k = 1 requires time O(mn log n/ log log n) and space O(n). We present two algorithms that require worst-case time O(mn) and O(n log^2 n), respectively, and space O(n), thus greatly improving the state of the art. Moreover, we present an algorithm that requires average-case time and space O(n) for integer alphabets if m = {\Omega}(log n/ log {\sigma}), where {\sigma} is the alphabet size

    A simpler and more efficient algorithm for the next-to-shortest path problem

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    Given an undirected graph G=(V,E)G=(V,E) with positive edge lengths and two vertices ss and tt, the next-to-shortest path problem is to find an stst-path which length is minimum amongst all stst-paths strictly longer than the shortest path length. In this paper we show that the problem can be solved in linear time if the distances from ss and tt to all other vertices are given. Particularly our new algorithm runs in O(VlogV+E)O(|V|\log |V|+|E|) time for general graphs, which improves the previous result of O(V2)O(|V|^2) time for sparse graphs, and takes only linear time for unweighted graphs, planar graphs, and graphs with positive integer edge lengths.Comment: Partial result appeared in COCOA201
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