Error minimization in approximate range aggregates

نویسندگان

  • Xuemin Lin
  • Qing Zhang
  • Yidong Yuan
  • Qing Liu
چکیده

Histogram techniques have been used in many commercial database management systems to estimate a query result size. Recently, it has been shown that they are very effective to support approximation of query processing especially aggregates. In this paper, we investigate the problem of minimizing average errors of approximate aggregates using histogram techniques. Firstly, we present a novel linear-spline histogram model that is more accurate than the existing models. Secondly, we propose a novel histogram construction technique for minimizing such average errors, which is shown to generate a near optimal histogram. Our experiment results demonstrate that the new histogram construction techniques lead to a great accuracy improvement on the existing techniques. 2006 Elsevier B.V. All rights reserved.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Approximate Closed-form Formulae for Buckling Analysis of Rectangular Tubes under Torsion

The buckling torque may be much less than the yield torque in very thin rectangular tubes under torsion. In this paper, simple closed-form formulae are presented for buckling analysis of long hollow rectangular tubes under torsion. By the presented formulae, one can obtain the critical torque or the critical angle of twist of the tube in terms of its geometrical parameters and material constant...

متن کامل

Global Error Minimization method for solving strongly nonlinear oscillator differential equations

A modified variational approach called Global Error Minimization (GEM) method is developed for obtaining an approximate closed-form analytical solution for nonlinear oscillator differential equations. The proposed method converts the nonlinear differential equation to an equivalentminimization problem. A trial solution is selectedwith unknown parameters. Next, the GEM method is used to solve th...

متن کامل

Efficient Approximation of Correlated Sums on Data Streams

In many applications such as IP network management, data arrives in streams, and queries over those streams need to be processed online using limited storage. Correlated-sum (CS) aggregates are a natural class of queries formed by composing basic aggregates on (x, y) pairs, and are of the form SUM{g(y) : x ≤ f(AGG(x))}, where AGG(x) can be any basic aggregate and f(), g() are user-specified fun...

متن کامل

Optimization of Multidimensional Aggregates in Data Warehouses

The computation of multidimensional aggregates is a common operation in OLAP applications. The major bottleneck is the large volume of data that needs to be processed which leads to prohibitively expensive query execution times. On the other hand, data analysts are primarily concerned with discerning trends in the data and thus a system that provides approximate answers in a timely fashion woul...

متن کامل

Iterative version of the QRD for adaptive RLS filtering

A modiied version of the QR{decomposition (QRD) is presented. It uses approximate Givens rotations instead of exact Givens rotations, i.e., a matrix entry usually annihilated with an exact rotation by an angle is only reduced by using an approximate rotation by an angle ~. The approximation of the rotations is based on the idea of CORDIC. Evaluating a CORDIC{based approximate rotation is to det...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Data Knowl. Eng.

دوره 62  شماره 

صفحات  -

تاریخ انتشار 2007