An Indexing Method to Construct Unbalanced Layers for High-Dimensional Data in Mobile Environments

Abstract

A top-query processing is widely used in many applications and mobile environments. An index is used for efficient query processing and layer-based indexing methods are representative to perform the top-query processing efficiently. However, the existing methods have a problem of high index building time for multidimensional and large data; thus, it is difficult to use them. In this paper, we proposed a new concept of constructing layer-based index, which is called unbalanced layer (UB-Layer). The existing methods construct a layer as a balanced layer with outermost data and wrap the rest of the input data. However, UBLayer constructs a layer as an unbalanced layer that does not wrap the rest of the data. To construct UB-Layer, we fist divide the dimension of the input data into divided-dimensional data and compute the convex hull in each divided-dimensional data. And then, we combine divided-convex hull to build UB-Layer. We also propose UB-SelectAttribute algorithm for dividing the dimension with major attributes. We demonstrate the superiority of the proposed methods by the performance experiments.

UB-H: an unbalanced-hierarchical layer binary-wise construction method for high-dimensional data

“…The existing methods focus on reducing the execution time and not increasing the number of layers. UB-Layer [14] is an unbalanced layer-based indexing method that reduces the construction time of the convex hull. The outer layer of the UB-Layer does not enclose other data objects as shown in Fig.…”

“…DS is divided into two sub-datasets, sub-DS 1 and sub-DS 2 , with four attributes each. We divide the attributes based on a UB-SelectAttribute algorithm [14] and consider the main attributes. In this paper, we assume that the attribute weights are the same, for simplicity.…”

“…However, when the number of training dataset is large and their dimension is high, the process of convex hull computation is time-consuming [13]. There have been various studies published, which aim to reduce the convex hull computation time [14][15][16]. Many existing studies have focused on reducing the computation time for constructing accurate convex hulls; however, these still do not resolve time complexity issues.…”

“…Furthermore, some recent studies have proposed significantly reducing the computation time by constructing an approximate convex hull. The unbalanced (UB)-layer [14] method is the result of one of the latest studies in constructing approximate convex hulls that is applicable to higherdimensional and larger databases. Figure 2 shows two lists of layers constructed Fig.…”

Spectrum Gap Analysis With Practical Solutions for Future Mobile Data Traffic Growth in Malaysia

“…In the past several years, the use of mobile data services has broadly and rapidly increased, becoming an essential and necessary addition in the lives of most mobile cellular users [1], [2]. Mobile data services are widely used by users, Internet-of-Things (IoT) applications [3]- [14], and Machineto-Machine (M2M) connections [15]- [23].…”