Yon Dohn Chung

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A prominent parallel data processing tool MapReduce is gaining significant momentum from both industry and academia as the volume of data to analyze grows rapidly. While MapReduce is used in many areas where massive data analysis is required, there are still debates on its performance, efficiency per node, and simple abstraction. This survey intends to(More)
This paper investigates how to place data objects on air for wireless broadcast such that mobile clients can access the data in short latency. We first define and analyze the problem of wireless data placement, and also propose a measure, named Query Distance (QD), which represents the coherence degree of data set accessed by a query. We show that the(More)
In wireless mobile computing environments, broadcasting is an effective and scalable technique to disseminate information to a massive number of clients, wherein the energy usage and latency are considered major concerns. This paper presents an indexing scheme for the energy- and latency-efficient processing of full-text searches over the wireless broadcast(More)
In this paper, we propose an energy and latency efficient XML dissemination scheme for the mobile computing. We define a novel unit structure called G-node for streaming XML data in the wireless environment. It exploits the benefits of the structure indexing and attribute summarization that can integrate relevant XML elements into a group. It provides a way(More)
RDF is a data model for representing labeled directed graphs, and it is used as an important building block of semantic web. Due to its flexibility and applicability, RDF has been used in applications, such as semantic web, bioinformatics, and social networks. In these applications, large-scale graph datasets are very common. However, existing techniques(More)
In this article, we address the problem of delayed query processing raised by tree-based index structures in wireless broadcast environments, which increases the access time of mobile clients. We propose a novel distributed index structure and a clustering strategy for streaming XML data that enables energy and latency-efficient broadcasting of XML data. We(More)
In this paper, we discuss the top-<i>k</i> monitoring over sensor networks. Since sensor readings are usually correlated with location, top-<i>k</i> nodes are clustered at some areas. Motivated by such a characteristic, we propose a novel tree structure named <i>partial ordered tree</i>(POT) to efficiently maintain clusters of the highest readings. By using(More)