The ever-increasing of spatial datasets and the widely application of the complex computation have motivated the emergence of distributed algorithms to process spatial operations efficiently. The R-tree index is broadly used by researches as a distributed spatial structure for indexing and retrieval of spatial objects. However, a big challenge has arisen, that is, how to check the consistency o...

Several applications require management of data which is spatially dynamic, e.g., tracking of battle ships or moving cells in a blood sample. The capability of handling the temporal aspect, i.e., the history of such type of data, is also important. This paper presents and evaluates three temporal extensions of the R-tree, the 3D R-tree, the 2+3 R-tree and the HR-tree, which are capable of index...

A very important class of spatial queries consists of nearestneighbor (NN) query and its variations. Many studies in the past decade utilize R-trees as their underlying index structures to address NN queries efficiently. The general approach is to use R-tree in two phases. First, R-tree’s hierarchical structure is used to quickly arrive to the neighborhood of the result set. Second, the R-tree ...

سپیدایی از ﭘﺎراﻣﺘﺮﻫﺎی ﻣﻮرد ﻧﻴﺎز در ﻣﻄﺎﻟﻌﺎت زﻳﺴﺖ‌ﻣﺤﻴﻄﻲ و آب‌و‌ﻫﻮاﻳﻲ به‌شمار می‌رود؛ ازاین‌رو، بررسی رفتار زمانی مکانی آن می‌تواند ابزاری برای شناخت تغییرات محیطی باشد. ﺳﻨﺠﻨﺪة مودیس ﺳﻄﺢ زﻣﻴﻦ را به‌طور ﻣﺴﺘﻤﺮ، ﻣﻘﻴﺎﺳﻲ ﺟﻬﺎﻧﻲ ﺑﺎ ﻗﺪرت ﺗﻔﻜﻴﻚ ﻣﻜﺎﻧﻲ مناسب ﺗﻮﻟﻴﺪ دسترس پژوهشگران ﻗﺮار داده است. این پژوهش، واکاوی موانع برداشت/ دیدبانی ایران‌زمین، نخست داده‌های روزانة سنجندة محدودة ایران، بازة 1/1/1379 تا 10/1...

A filling subgroup of a finitely generated free group F (X) is a subgroup which does not fix a point in any very small action free action on an R-tree. For the free group of rank two, we construct a combinatorial algorithm to determine whether or not a given finitely generated subgroup is filling. In higher ranks, we discuss two types of non-filling subgroups: those contained in loop vertex sub...

Since its introduction in 1984, R-tree has been proven to be one of the most practical and well-behaved data structures for accommodating dynamic massive sets of geometric objects and conducting a very diverse set of queries on such datasets in real-world applications. This success has led to a variety of versions, each one trying to tune the performance parameters of the original proposal. Amo...

ÐSelection and join queries are fundamental operations in Data Base Management Systems (DBMS). Support for nontraditional data, including spatial objects, in an efficient manner is of ongoing interest in database research. Toward this goal, access methods and cost models for spatial queries are necessary tools for spatial query processing and optimization. In this paper, we present analytical m...

We propose a new Rtree structure that outperforms all the older ones. The heart of the idea is to facilitate the deferred splitting ap preach in R-trees. This is done by proposing an ordering on the R-tree nodes. This ordering has to be ‘good’, in the sense that it should group ‘similar’ data rectangles to gether, to minimize the area and perimeter of the resulting minimum bounding rectangles (...

A geodesic lamination L on a closed hyperbolic surface S, when provided with a transverse measure μ, gives rise to a “dual R-tree” Tμ, together with an action of G = π1S on Tμ by isometries. A point of Tμ corresponds precisely to a leaf of the lift L̃ of L to the universal covering S̃ of S, or to a complementary component of L̃ in S̃. The G-action on T is induced by the G-action on S̃ as deck transf...