• Journal of Information Processing Systems
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• v.17 no.1
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• pp.37-50
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• 2021

Query applications based on nested data, the most commonly used form of data representation on the web, especially precise query, is becoming more extensively used. MapReduce, a distributed architecture with parallel computing power, provides a good solution for big data processing. However, in practical application, query requests are usually concurrent, which causes bottlenecks in server processing. To solve this problem, this paper first combines a column storage structure and an inverted index to build index for nested data on MapReduce. On this basis, this paper puts forward an optimization strategy which combines query execution service tree and frequent sub-query trajectory to reduce the response time of frequent queries and further improve the efficiency of multi-user concurrent queries on large scale nested data. Experiments show that this method greatly improves the efficiency of nested data query.

• Journal of the Korean Statistical Society
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• v.30 no.4
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• pp.541-550
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• 2001

This paper considers a panel data regression model in which the disturbances follow a nested error components with serial correlation. Given this model, this paper derives several Lagrange Multiplier(LM) testis for the presence of serial correlation as well as random individual effects, nested effects, and for existence of serial correlation given random individual and nested effects.

• Journal of the Korean Data and Information Science Society
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• v.19 no.4
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• pp.1059-1071
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• 2008

In a balanced factorial design with a nested factor where crossed factors as well as a nested factor exist simultaneously, powers of the rank transformed FR statistic for testing the main, nested and interaction effects are superior to those of the parametric F statistic. In heavy tailed distributions such as exponential and double exponential distributions, powers of the FR statistic show much higher level than those of the F statistic. Further powers of the F and FR statistic for testing the main effect show the highest level in an absolute size as compared with powers of the F and FR statistic for testing the nested and interaction effects. However powers of the FR statistic for testing the nested and interaction effects rather than the main effect are greater in a relative size than powers of F statistic for the all population distributions.

• Journal of the Korean Data and Information Science Society
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• v.17 no.1
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• pp.187-193
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• 2006

This paper shows how to use continuation-ratio logits for the analysis of structured polytomous data. Here, response categories are considered to have a nested binary structure. Thus, conditionally nested binary random variables can be defined in each step. Two types of factors are considered as independent variables affecting response probabilities. For the purpose of analyzing categorical data with binary nested strutures a continuation-ratio mixed model is suggested. Estimation procedure for the unknown parameters in a suggested model is also discussed in detail by an example.

• Journal of the Korean Statistical Society
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• v.28 no.4
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• pp.489-501
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• 1999

In this paper, we consider the panel data regression model in which the disturbances have nested error component. We derive a Lagrange Multiplier(LM) test which is jointly testing for the presence of random individual effects and nested effects under the normality assumption of the disturbances. This test extends the earlier work of Breusch and Pagan(1980) and Baltagi and Li(1991). Further, it is shown that this LM test has the same asymptotic distribution without normality assumption of the disturbances.

• Journal of the Korean Statistical Society
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• v.29 no.1
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• pp.63-80
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• 2000

We consider the panel data regression model with nested error componets. In this paper, the several Lagrange Multipler tests for the nested error component model are derived. These tests extend the earlier work of Honda(1985), Moulton and Randolph(1989), Baltagi, et al.(1992) and King and Wu(1997) to the nested error component case. Monte Carlo experiments are conducted to study the performance of these LM tests.

• The Korean Journal of Applied Statistics
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• v.14 no.1
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• pp.103-110
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• 2001

This paper considers a multistage experiment. Response scales can be same or different from stage to stage. When variables are of nested structure, the response variable at each stage can be defined conditionally. For analysing such data with compound scales, this paper suggests a sequnce of dependence models and shows how to set up a sequence of models for the driver's liscense test data.

• Communications for Statistical Applications and Methods
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• v.16 no.4
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• pp.659-667
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• 2009

Recently Song and Cheon (2006) and Cheon and Lim (2009) developed the generalized maximum entropy(GME) estimator to solve ill-posed problems for the regression coefficients in the simple panel model. The models discussed consider the individual and a spatial autoregressive disturbance effects. However, in many application in economics the data may contain nested groupings. This paper considers a two-way error component model with nested groupings for the ill-posed data and proposes the GME estimator of the unknown parameters. The performance of this estimator is compared with the existing methods on the simulated dataset. The results indicate that the GME method performs the best in estimating the unknown parameters in terms of its quality when the data are ill-posed.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.11a
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• pp.27-30
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• 2005

XML(Extensible Markup Language)이 데이터 표현(data representation)과 문서 교환(data exchange)의 표준으로 지정됨에 따라 데이터베이스(database, DB)에 XML 문서를 저장하고 질의하기 위한 연구가 활발히 진행되고 있다. 특히, 현재 주류를 이루고 있는 관계형 DB 에 저장하기 위한 XML 인덱싱(indexing) 기법에 대한 연구도 다양하게 진행되고 있다. 본 논문에서는 XML 문서를 관계형 DB 에 효율적으로 저장하고 질의하기 위한 방법으로서 기존의 트리(tree) 구조의 데이터를 관계형 DB 에 Nested Interval 인덱싱 기법을 적용하여 XML 문서를 저장하는 방법에 대해 연구한다. 기존의 저장 기법들의 경우 XML 문서를 효율적으로 질의하기 위한 인덱싱을 수행하기 때문에 입력 후 추가되는 노드(node), 혹은 노드 집합의 입력 시에는 전체 혹은 일부분의 XML 문서를 재-인덱싱 해야 하는 비효율이 있다. 그러나, Nested Interval 의 경우에는 재-인덱싱이 불필요하다. 본 논문에서는 기존의 트리 구조 데이터의 인덱싱 기법들에 대한 비교와 함께 Nested Interval 을 이용한 XML 문서의 인덱싱 기법에 대해 기술한다.

• Journal of the Korean Data and Information Science Society
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• v.13 no.2
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• pp.129-138
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• 2002

This paper deals with logistic regression models for analysing separation rates from majors. The model building procedure shows how to incoporate the effects of some factors causing from three-way nested sampling scheme and discusses what type of characteristics as independent variables directly affecting the rates should be considered.