Linear-time top-k sort method

Abstract

The present invention relates to an algorithm that retrieves only k data elements having the largest (or smallest) key values from a dataset (i.e., top-k results) in a time linearly proportional to the size of the dataset. The proposed method using the algorithm finds the top-k results using a k-sized min (or max) heap structure that maintains candidate elements of the top-k results by scanning all data elements in the dataset only once. In other words, the present invention provides a linear-time top-k sort method that finds top-k results in a time linearly proportional to the size of the dataset (i.e., O(n) time complexity), while conventional sort algorithms for finding top-k results cannot find the top-k results in a time linearly proportional to the size of the dataset (i.e., at least O(n log n) time complexity).

Description

CROSS-REFERENCES TO RELATED APPLICATIONS[0001]This patent application claims priority from and the benefit of Korean Patent Application No. 10-2011-0037332, filed on Apr. 21, 2011, which is hereby incorporated by reference for all purposes as if fully set forth herein.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The invention relates to a linear-time top-k sort method, and more specifically, to an algorithm that retrieves only k elements (i.e., top-k results) having the largest (or smallest) key values from a dataset in a sorted order in a time proportional to the dataset size.[0004]2. Description of the Related Art[0005]Recently, wide use of Internet and the convergence of digital technologies have caused a significant increase in the amount of data that need to be processed by application systems with limited resources.[0006]In particular, in Web and multimedia search systems or distributed systems that deal with a huge amount of data, it is sometimes difficult ...

AI Technical Summary

Benefits of technology

[0015]The objective of the present invention is to provide an efficient algorithm that retrieves only k data elements having the largest (or smallest) key values in the descending (or ascending) order from a dataset of n data elements having key values in a linear time (i.e., O(n) time complexity) in place of expensive conventional sort algorithms having O(n log n) time complexities as mentioned in ‘Related Art 2’.

[0033]In one embodiment, the liner-time top-k sort method, which finds top-k results from a huge amount of data efficiently compared with the convectional sort algorithms, is provided. Since the method has O(n) time complexity, its execution time increases linearly in the size of the dataset (n). This property solves the inefficiency problem of the conventional sort algorithms that have O(n log n) time complexities.

[0035]More specifically, the method reduces storage space for maintaining top-k results drastically since it needs a constant amount of storage space (i.e., O(k)) regardless of the size of the dataset, while conventional sort algorithms need storage space whose size is proportional to the size of dataset (i.e., O(n)).

[0036]In one embodiment, the method is applicable to the commercialization of the method itself or to the development of large-scale Web search engines and distributed systems that support top-k results. It is expected to enhance the performance of those systems significantly.

Problems solved by technology

Also, the present inventive concept is not required to overcome the disadvantages described above, and an exemplary embodiment of the present inventive concept may not overcome any of the problems described above.

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