نتایج جستجو برای: r میانه ممانعتی

تعداد نتایج: 451830  

ژورنال: پژوهش های زبانی 2013
آژیده مقدم, نرگس نعمت الهی

فعل در زبان­های ایرانی باستان بر مبنای زمان، نمود، شخص، شمار و دو جهتِ اکتیو و میانه بررسی می‌شود. بنابر دیدگاه رایج، جهت میانه وسیلۀ تبدیل ریشه­های گذرا به ناگذر است. این دیدگاه با مشاهدۀ ریشه­هایی فعلی شکل گرفته است که در جهت اکتیو، گذرا و در جهت میانه ناگذر هستند، در حالی ‌که  بررسی دقیق­تر متون بازمانده از زبان­های باستانی ایران،  ویژگی­های دیگری را آشکار می­کند که اعتبار نظریۀ فوق را به چال...

1998
Scott T. Leutenegger Mario A. López

ÐPast R-tree studies have focused on the number of nodes visited as a metric of query performance. Since database systems usually include a buffering mechanism, we propose that the number of disk accesses is a more realistic measure of performance. We develop a buffer model to analyze the number of disk accesses required for spatial queries using R-trees. The model can be used to evaluate the q...

2003
Jing Shan Donghui Zhang Betty Salzberg

An important query for spatial database research is to find the closest pair of objects in a given space. Existing work assumes two objects of the closest pair come from two different data sets indexed by R-trees. The closest pair in the whole space will be found via an optimzed R-tree join technique. However, this technique doesn’t perform well when the two data sets are identical. And it does...

2003
Sudipto Guha Nick Koudas Divesh Srivastava Ting Yu

XML data integration tools are facing a variety of challenges for their efficient and effective operation. Among these is the requirement to handle a variety of inconsistencies or mistakes present in the data sets. In this paper we study the problem of integrating XML data sources through index assisted join operations, using notions of approximate match in the structure and content of XML docu...

2003
Sham Prasher Xiaofang Zhou

Many emerging applications benefit from the extraction of geospatial data specified at different resolutions for viewing purposes. Data must also be topologically accurate and up-to-date as it often represents real-world changing phenomena. Current multiresolution schemes use complex opaque data types, which limit the capacity for in-database object manipulation. By using z-values and B+trees t...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشکده علوم پایه 1386

چکیده ندارد.

2000
Dieter Pfoser Christian S. Jensen Yannis Theodoridis

The domain of spatiotemporal applications is a treasure trove of new types of data and queries. However, work in this area is guided by related research from the spatial and temporal domains, so far, with little attention towards the true nature of spatiotemporal phenomena. In this work, the focus is on a spatiotemporal sub-domain, namely the trajectories of moving point objects. We present new...

1999
Rupesh Choubey Li Chen Elke A. Rundensteiner

A lot of recent work has studied strategies related to bulk loading of large data sets into multidimensional index structures In this paper we address the problem of bulk insertions into existing index struc tures with particular focus on R trees which are an important class of index structures used widely in commercial database systems We pro pose a new technique which as opposed to the curren...

2011
Qianlu Lin Chuan Xiao Muhammad Aamir Cheema Wei Wang

Finding the most accessible locations has a number of applications. For example, a user may want to find an accommodation that is close to different amenities such as schools, supermarkets, and hospitals etc. In this paper, we study the problem of finding the most accessible locations among a set of possible sites. The task is converted to a top-k query that returns k points from a set of sites...

2000
Inga Sitzmann Peter J. Stuckey

Constraint search trees are a generic approach to search trees where all operations are defined in terms of constraints. This abstract viewpoint makes clear the fundamental operations of search trees and immediately points to new possibilities for search trees. In this paper we present height-balanced constraint search trees (HCSTs), a general approach to building height-balanced index structur...

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