• KIPS Transactions on Software and Data Engineering
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• v.6 no.2
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• pp.103-116
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• 2017

In this paper, we present the design and implementation of a large-scale qualitative spatial reasoner, which can derive new qualitative spatial knowledge representing both topological and directional relationships between two arbitrary spatial objects in efficient way using Aparch Spark SQL. Apache Spark SQL is well known as a distributed parallel programming environment which provides both efficient join operations and query processing functions over a variety of data in Hadoop cluster computer systems. In our spatial reasoner, the overall reasoning process is divided into 6 jobs such as knowledge encoding, inverse reasoning, equal reasoning, transitive reasoning, relation refining, knowledge decoding, and then the execution order over the reasoning jobs is determined in consideration of both logical causal relationships and computational efficiency. The knowledge encoding job reduces the size of knowledge base to reason over by transforming the input knowledge of XML/RDF form into one of more precise form. Repeat of the transitive reasoning job and the relation refining job usually consumes most of computational time and storage for the overall reasoning process. In order to improve the jobs, our reasoner finds out the minimal disjunctive relations for qualitative spatial reasoning, and then, based upon them, it not only reduces the composition table to be used for the transitive reasoning job, but also optimizes the relation refining job. Through experiments using a large-scale benchmarking spatial knowledge base, the proposed reasoner showed high performance and scalability.

• KIISE Transactions on Computing Practices
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• v.21 no.12
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• pp.774-779
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• 2015

In this paper, we present the design and implementation of a large-scale qualitative spatial reasoner using Apache Spark, an in-memory high speed cluster computing environment, which is effective for sequencing and iterating component reasoning jobs. The proposed reasoner can not only check the integrity of a large-scale spatial knowledge base representing topological and directional relationships between spatial objects, but also expand the given knowledge base by deriving new facts in highly efficient ways. In general, qualitative reasoning on topological and directional relationships between spatial objects includes a number of composition operations on every possible pair of disjunctive relations. The proposed reasoner enhances computational efficiency by determining the minimal set of disjunctive relations for spatial reasoning and then reducing the size of the composition table to include only that set. Additionally, in order to improve performance, the proposed reasoner is designed to minimize disk I/Os during distributed reasoning jobs, which are performed on a Hadoop cluster system. In experiments with both artificial and real spatial knowledge bases, the proposed Spark-based spatial reasoner showed higher performance than the existing MapReduce-based one.

• KIPS Transactions on Software and Data Engineering
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• v.5 no.5
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• pp.231-242
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• 2016

In order to meet rapid changes of Web information, it is necessary to extend the current Web technologies to represent both the valid time and location of each fact and knowledge, and reason their relationships. Until recently, many researches on qualitative temporal reasoning have been conducted in laboratory-scale, dealing with small knowledge bases. However, in this paper, we propose the design and implementation of a parallel qualitative temporal reasoner, MRQUTER, which can make reasoning over Web-scale large knowledge bases. This parallel temporal reasoner was built on a Hadoop cluster system using the MapReduce parallel programming framework. It decomposes the entire qualitative temporal reasoning process into several MapReduce jobs such as the encoding and decoding job, the inverse and equal reasoning job, the transitive reasoning job, the refining job, and applies some optimization techniques into each component reasoning job implemented with a pair of Map and Reduce functions. Through experiments using large benchmarking temporal knowledge bases, MRQUTER shows high reasoning performance and scalability.

• Cross-Cultural Studies
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• v.24
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• pp.46-61
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• 2011

This paper considers how Koreans found their positions in the complex, overlapping, disjunctive, and interconnected "Oriental" repertoires in the early Cold War years. When we use the term, Oriental, it should require careful translation from context to context because it may be subject to very different sets of contextual circumstances. Klein views Cold War Orientalism in the complex of various regions including East Asian and Southeast Asian countries; however, when Koreans are contextualized at the center of the discussion the Orientalism produces another discursive meaning. Even though many great researches have been done on Korean immigrations, Korean American literatures, and US-Korea economic, political, and foreign relations, not many discussions about Korean American popular cultures have been discussed in the basis of the Oriental discourse in the United States.For this argument, this paper investigates the performative trajectory of a girl group "Kim Sisters" who began to sing at the US military show stages in South Korea in 1952 during the Korean War. They moved to Las Vegas show stages in 1959 and later appeared in Ed Sullivan Show more than thirty times during the 1960s and 70s. Meanwhile, they not only returned to South Korea often times to perform at the stages for Korean audiences in South Korea but also played at the shows for Korean immigrants in the United States. Korean American immigration to the United States has followed a different route from the majority of Asian American population such as Chinese or Japanese Americans, which means that efforts to compare this particular group to the others may be unnecessary. Rather doing comparative studies, this paper, therefore, focuses on the formation of the intersecting and multiple identities of Korean female entertainers who were forced or forced themselves to be incorporated into the American popular "Oriental" imagination, which I would call "embedded" identities. This embeddedness has been continuously maintained in the configuration of Korean characters in the United States. This will help not only to observe the discursive aspect of Asian American identity politics but also to claim a space for comparatively invisible Korean characters in the United States which has been often times neglected and not brought into a major Asian American or Oriental historical discourse. This paper starts with American scenes at the beginning of the twentieth century to trace Americans Oriental imagination which was observable in the various American cultural landscape and popular music soundscape. It will help us more clearly understand the production and consumption of the Korean "Oriental" performances during the early Cold War period and especially the Korean performance in the American venue, silently overshadowed into the political, social, and cultural framework.