733 research outputs found
Range Queries on Uncertain Data
Given a set of uncertain points on the real line, each represented by
its one-dimensional probability density function, we consider the problem of
building data structures on to answer range queries of the following three
types for any query interval : (1) top- query: find the point in that
lies in with the highest probability, (2) top- query: given any integer
as part of the query, return the points in that lie in
with the highest probabilities, and (3) threshold query: given any threshold
as part of the query, return all points of that lie in with
probabilities at least . We present data structures for these range
queries with linear or nearly linear space and efficient query time.Comment: 26 pages. A preliminary version of this paper appeared in ISAAC 2014.
In this full version, we also present solutions to the most general case of
the problem (i.e., the histogram bounded case), which were left as open
problems in the preliminary versio
Finding Pairwise Intersections Inside a Query Range
We study the following problem: preprocess a set O of objects into a data
structure that allows us to efficiently report all pairs of objects from O that
intersect inside an axis-aligned query range Q. We present data structures of
size and with query time
time, where k is the number of reported pairs, for two classes of objects in
the plane: axis-aligned rectangles and objects with small union complexity. For
the 3-dimensional case where the objects and the query range are axis-aligned
boxes in R^3, we present a data structures of size and query time . When the objects and
query are fat, we obtain query time using storage
Orthogonal Range Reporting and Rectangle Stabbing for Fat Rectangles
In this paper we study two geometric data structure problems in the special
case when input objects or queries are fat rectangles. We show that in this
case a significant improvement compared to the general case can be achieved.
We describe data structures that answer two- and three-dimensional orthogonal
range reporting queries in the case when the query range is a \emph{fat}
rectangle. Our two-dimensional data structure uses words and supports
queries in time, where is the number of points in the
data structure, is the size of the universe and is the number of points
in the query range. Our three-dimensional data structure needs
words of space and answers queries in time. We also consider the rectangle stabbing problem on a set of
three-dimensional fat rectangles. Our data structure uses space and
answers stabbing queries in time.Comment: extended version of a WADS'19 pape
Dairy product consumption in french children in 2010
Dairy food consumption is important for children as it contributes to the intake of key nutrients, especially calcium. The aim of the present paper is to provide an overview of dairy products consumption for French children, according to age, sex and type of dairy products. Adequacy of dairy and calcium intakes in line with French national guidelines "3 portions of dairy products per day" were also evaluated. Data were extracted and analyzed from the CCAF-Comportementet Consommations Alimentairesen France-study. Seven-day questionnaires were administered to free-living individuals from autumn 2009 to summer 2010. Subjects were children (n=1171) aged 3-17 years. Dairy products contributed substantially to the intake of calcium, phosphorus, potassium, zinc, vitamin B2 and vitamin B12. A general decrease in DP consumption has been observed since 2003. This is most notably due to a lower milk intake which is not compensated by increased cheese or fresh dairy products. Most of children (67%), and up to 73% of adolescents (15 - 17 y), did not reach the recommended "3 servings of dairy products per day". Twenty percent of children from the age of 6 and nearly 2/3 of female adolescents did not reach their estimated average requirement for calcium. The overview of French dairy food consumption during childhood, of particular Public Health concern, emphasizes the need to encourage dairy consumption and particularly milk consumption at breakfast in order to maintain a nutrient adequacy in children and adolescents
Subsampling in Smoothed Range Spaces
We consider smoothed versions of geometric range spaces, so an element of the
ground set (e.g. a point) can be contained in a range with a non-binary value
in . Similar notions have been considered for kernels; we extend them to
more general types of ranges. We then consider approximations of these range
spaces through -nets and -samples (aka
-approximations). We characterize when size bounds for
-samples on kernels can be extended to these more general
smoothed range spaces. We also describe new generalizations for -nets to these range spaces and show when results from binary range spaces can
carry over to these smoothed ones.Comment: This is the full version of the paper which appeared in ALT 2015. 16
pages, 3 figures. In Algorithmic Learning Theory, pp. 224-238. Springer
International Publishing, 201
Computing the Largest Empty Rectangle
We consider the following problem: Given a rectangle containing N points, find the largest area subrectangle with sides parallel to those of the original rectangle which contains none of the given points. If the rectangle is a piece of fabric or sheet metal and the points are flaws, this problem is finding the largest-area rectangular piece which can be salvaged. A previously known result [13] takes worst-case and expected time. This paper presents an time, space algorithm to solve this problem. It uses a divide-and-conquer approach similar to the ones used by Bentley [1] and introduces a new notion of Voronoi diagram along with a method for efficient computation of certain functions over paths of a tree
Virus Propagation in Multiple Profile Networks
Suppose we have a virus or one competing idea/product that propagates over a
multiple profile (e.g., social) network. Can we predict what proportion of the
network will actually get "infected" (e.g., spread the idea or buy the
competing product), when the nodes of the network appear to have different
sensitivity based on their profile? For example, if there are two profiles
and in a network and the nodes of profile
and profile are susceptible to a highly spreading
virus with probabilities and
respectively, what percentage of both profiles will actually get infected from
the virus at the end? To reverse the question, what are the necessary
conditions so that a predefined percentage of the network is infected? We
assume that nodes of different profiles can infect one another and we prove
that under realistic conditions, apart from the weak profile (great
sensitivity), the stronger profile (low sensitivity) will get infected as well.
First, we focus on cliques with the goal to provide exact theoretical results
as well as to get some intuition as to how a virus affects such a multiple
profile network. Then, we move to the theoretical analysis of arbitrary
networks. We provide bounds on certain properties of the network based on the
probabilities of infection of each node in it when it reaches the steady state.
Finally, we provide extensive experimental results that verify our theoretical
results and at the same time provide more insight on the problem
Query processing of spatial objects: Complexity versus Redundancy
The management of complex spatial objects in applications, such as geography and cartography,
imposes stringent new requirements on spatial database systems, in particular on efficient
query processing. As shown before, the performance of spatial query processing can be improved
by decomposing complex spatial objects into simple components. Up to now, only decomposition
techniques generating a linear number of very simple components, e.g. triangles or trapezoids, have
been considered. In this paper, we will investigate the natural trade-off between the complexity of
the components and the redundancy, i.e. the number of components, with respect to its effect on
efficient query processing. In particular, we present two new decomposition methods generating
a better balance between the complexity and the number of components than previously known
techniques. We compare these new decomposition methods to the traditional undecomposed representation
as well as to the well-known decomposition into convex polygons with respect to their
performance in spatial query processing. This comparison points out that for a wide range of query
selectivity the new decomposition techniques clearly outperform both the undecomposed representation
and the convex decomposition method. More important than the absolute gain in performance
by a factor of up to an order of magnitude is the robust performance of our new decomposition
techniques over the whole range of query selectivity
Dynamic tree shortcut with constant degree
LNCS v.9188 entitled: Computing and Combinatorics: 21st International Conference, COCOON 2015, Beijing, China, August 4-6, 2015, ProceedingsGiven a rooted tree with n nodes, the tree shortcut problem is to add a set of shortcut edges to the tree such that the shortest path from each node to any of its ancestors is of length O(log n) and the degree increment of each node is constant. We consider in this paper the dynamic version of the problem, which supports node insertion and deletion. For insertion, a node can be inserted as a leaf node or an internal node by sub-dividing an existing edge. For deletion, a leaf node can be deleted, or an internal node can be merged with its single child. We propose an algorithm that maintains a set of shortcut edges in O(log n) time for an insertion or deletion.postprin
- …