202 results on '"Hiroshi Kurata"'
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2. A SPECIAL PROPERTY OF RESISTANCE MATRICES.
- Author
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BALAJI, R., LATHER, GARGI, HIROSHI KURATA, and GUPTA, VINAYAK
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LAPLACIAN matrices ,GRAPH connectivity ,COMPLETE graphs ,MATRICES (Mathematics) - Abstract
We deduce a new property exhibited by the resistance matrices of connected graphs. Specifically, we show that if R=(r
ij ) is the resistance matrix of a connected graph on n vertices, then every off-diagonal entry in the Moore-Penrose inverse of ... is negative. Thus, we establish that the Moore-Penrose inverse of the resistance Laplacian matrices are M-matrices. [ABSTRACT FROM AUTHOR]- Published
- 2024
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3. Some theorems on the core inverse of matrices and the core partial ordering.
- Author
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Hiroshi Kurata
- Published
- 2018
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4. On cell matrices: A class of Euclidean distance matrices.
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Pablo Tarazaga and Hiroshi Kurata
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- 2014
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5. Principal points of a multivariate mixture distribution.
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Shun Matsuura and Hiroshi Kurata
- Published
- 2011
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6. A higher-cost region excessively attracts firms
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Takao Ohkawa, Makoto Okamura, and Hiroshi Kurata
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Economic efficiency ,0502 economics and business ,05 social sciences ,Geography, Planning and Development ,Economics ,Aerospace Engineering ,050207 economics ,Development ,Social efficiency ,Industrial organization - Abstract
This study examines the economic efficiency associated with firm location in a non-traded goods industry. This industry comprises of two segmented regions (markets) and a fixed number of potentiall...
- Published
- 2020
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7. Vertical specialization in North-South trade : Industrial relocation, wage and welfare
- Author
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Nobuhito Suga, Ryoichi Nomura, and Hiroshi Kurata
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Vertical specialization ,media_common.quotation_subject ,Geography, Planning and Development ,Wage ,International economics ,Development ,Trade cost ,Reshoring ,Economics ,Production (economics) ,Relocation ,Welfare ,media_common - Abstract
This paper presents a North–South trade model with vertically linked industries and examines how declining costs of trade across stages of production encourage vertical specialization and affect wages and welfare. As trade costs fall below a threshold, the production of all final goods relocates to the South and vertical specialization emerges. In some industries, production of intermediate goods also relocates against comparative costs because of benefits of co‐location, and further declines in trade costs lead to reshoring. A country may temporarily lose from falling trade costs, but both countries can be better off after trade costs fall sufficiently.
- Published
- 2020
8. Determining the minimum rank of matroids whose basis graph is common.
- Author
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Masahiro Hachimori, Hiroshi Kurata, and Tadashi Sakuma
- Published
- 2008
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9. Standards policy and international trade: Multilateralism versus regionalism
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Yasuhiro Takarada, Akihiko Yanase, Yasushi Kawabata, and Hiroshi Kurata
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Economics and Econometrics ,Sociology and Political Science ,business.industry ,media_common.quotation_subject ,05 social sciences ,Harmonization ,International trade ,Safety standards ,Multilateralism ,Final good ,0502 economics and business ,Regionalism (international relations) ,Economics ,050206 economic theory ,050207 economics ,business ,Fixed cost ,Welfare ,Finance ,Externality ,media_common - Abstract
We develop a simple model of policy coordination on domestic standards and examine whether domestic standards policy can lead to regional and multilateral harmonization of standards under the principle of national treatment. This paper focuses on mandatory product and process standards affecting the characteristics of a final good that control negative consumption externalities (e.g., vehicle emissions control and safety standards, restrictions on the use of pesticides for agricultural goods, and safety standards for electrical products). Only the products that meet a country's national standards are allowed to circulate in that country's market. Raising standards reduces negative externalities caused by consumption of a traded good but increases firms’ costs. We use the core as the solution concept. A standards regime is considered to be in the core if it is not blocked by any coalition within countries. The main finding is that a multilateral agreement on standards that maximizes world welfare is only in the core if externalities are local or slightly transboundary. Otherwise, only a regional agreement on standards is in the core. As extensions, we consider many and asymmetric number of firms, asymmetry in market size, fixed costs for different standards, and a multilateral agreement on different standards.
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- 2020
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10. Covariance matrix estimation in a seemingly unrelated regression model under Stein’s loss
- Author
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Hiroshi Kurata and Shun Matsuura
- Subjects
Statistics and Probability ,Covariance matrix ,Estimator ,Regression analysis ,Function (mathematics) ,Seemingly unrelated regressions ,01 natural sciences ,Connection (mathematics) ,010104 statistics & probability ,Linear regression ,Statistics::Methodology ,Applied mathematics ,Equivariant map ,0101 mathematics ,Statistics, Probability and Uncertainty ,Mathematics - Abstract
A seemingly unrelated regression model has been commonly used for describing a set of different regression models with correlations. This paper discusses the estimation of the covariance matrix in a seemingly unrelated regression model under Stein’s loss function. In particular, when the correlation matrix is assumed to be known, a best equivariant estimator of the covariance matrix is derived. Its properties are investigated and a connection to a best equivariant estimator of regression coefficients given in a previous study is shown. Results of numerical simulations and an illustrative example are also presented to compare the best equivariant estimator of the covariance matrix with several conventional covariance matrix estimators.
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- 2019
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11. On Cartesian product of Euclidean distance matrices
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Hiroshi Kurata and Ravindra B. Bapat
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Kronecker product ,Numerical Analysis ,Algebra and Number Theory ,010102 general mathematics ,Minor (linear algebra) ,010103 numerical & computational mathematics ,Function (mathematics) ,Rank (differential topology) ,Cartesian product ,01 natural sciences ,Combinatorics ,symbols.namesake ,Matrix (mathematics) ,Product (mathematics) ,symbols ,Discrete Mathematics and Combinatorics ,Order (group theory) ,Geometry and Topology ,0101 mathematics ,Mathematics - Abstract
If A ∈ R m × m and B ∈ R n × n , we define the product A ⊘ B as A ⊘ B = A ⊗ J n + J m ⊗ B , where ⊗ denotes the Kronecker product and J n is the n × n matrix of all ones. We refer to this product as the Cartesian product of A and B since if D 1 and D 2 are the distance matrices of graphs G 1 and G 2 respectively, then D 1 ⊘ D 2 is the distance matrix of the Cartesian product G 1 □ G 2 . We study Cartesian products of Euclidean distance matrices (EDMs). We prove that if A and B are EDMs, then so is the product A ⊘ B . We show that if A is an EDM and U is symmetric, then A ⊗ U is an EDM if and only if U = c J n for some c. It is shown that for EDMs A and B, A ⊘ B is spherical if and only if both A and B are spherical. If A and B are EDMs, then we derive expressions for the rank and the Moore–Penrose inverse of A ⊘ B . In the final section we consider the product A ⊘ B for arbitrary matrices. For A ∈ R m × m , B ∈ R n × n , we show that all nonzero minors of A ⊘ B of order m + n − 1 are equal. An explicit formula for a nonzero minor of order m + n − 1 is proved. The result is shown to generalize the familiar fact that the determinant of the distance matrix of a tree on n vertices does not depend on the tree and is a function only of n.
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- 2019
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12. Generalized Least Squares
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Takeaki Kariya, Hiroshi Kurata
- Published
- 2004
13. Agritourism, Unemployment, and Urban-Rural Migration
- Author
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Kenji Kondoh and Hiroshi Kurata
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Labour economics ,geography ,geography.geographical_feature_category ,media_common.quotation_subject ,Wage ,Developing country ,Investment (macroeconomics) ,Urban area ,Unemployment ,Economics ,Rural area ,Welfare ,Tourism ,media_common - Abstract
This study examines the effects of policy changes and improvements in the agritourism sector in a developing country. We analyze the economy of a developing country, which consists of two regions: an urban area where the manufacturing sector is located and which has a certain level of unemployment a la Harris and Todaro (Am Econ Rev 60(1):126–142, 1970), and a rural area where both the agricultural and agritourism sectors are located. We demonstrate that encouraging labor outflow is reasonable, while the effects of a decrease in the minimum urban wage or the effects of additional foreign capital investment are not clear. We also assert that under certain conditions, an enhancement of the ratio of agricultural goods to touristic services in the agritourism sector will improve domestic welfare and reduce the urban unemployment rate. Furthermore, we conclude that agricultural-good-intensive tourism and environmentally friendly agritourism cause positive effects on welfare and employment.
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- 2021
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14. Occurrence of Bacillus cereus in Meat Products, Raw Meat and Meat Product Additives
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Hiroshi Kurata, Sumio Konno, Kunihiro Shinagawa, Masakazu Tokumaru, Tamotsu Shigehisa, Yoshihiro Kuwabara, Carlos A. M. Lopes, Hirota Konuma, Norio Fujino, and Youichi Onoue
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Meat packing industry ,business.industry ,Bacillus cereus ,food and beverages ,Biology ,Contamination ,biology.organism_classification ,Microbiology ,Animal proteins ,Cereus ,Meat spoilage ,Food science ,Raw meat ,business ,Food Science - Abstract
One thousand nine hundred and sixty three samples of meat products, raw meat and meat product additives from different slaughterhouses, meat processing factories and retail meat shops in six prefectures of Japan, were examined for the presence and number of Bacillus cereus . Although B. cereus was found in meat products (18.3%) and raw meat (6.6%), the contamination levels were generally lower than 102 per gram. In contrast, meat product additives showed contamination levels ranging from 102 to 104/g with the highest values (104/g) in samples of spices and animal proteins. On the basis of these results, we suggest that the main source of B. cereus contamination in meat products is contaminated meat product additives.
- Published
- 2019
15. Fundamental Knowledge of Bleaching Chemicals
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Hiroshi Kurata
- Subjects
Mechanical Engineering ,Media Technology ,General Materials Science ,General Chemistry - Published
- 2017
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16. Optimal estimators of principal points for minimizing expected mean squared distance
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Thaddeus Tarpey, Hiroshi Kurata, and Shun Matsuura
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Statistics and Probability ,Normal distribution ,Cardinal point ,Applied Mathematics ,Statistics ,Nonparametric statistics ,Degrees of freedom (statistics) ,Univariate ,Estimator ,Statistics, Probability and Uncertainty ,Random variable ,Location-scale family ,Mathematics - Abstract
k -Principal points of a random variable are k points that minimize the mean squared distance (MSD) between the random variable and the nearest of the k points. This paper focuses on finding optimal estimators of principal points in terms of the expected mean squared distance (EMSD) between the random variable and the nearest principal point estimator. These estimators are compared with nonparametric and maximum likelihood estimators. It turns out that a minimum EMSD estimator of k -principal points of univariate normal distributions is determined by the k -principal points of the t -distribution with n + 1 degrees of freedom, where n is the sample size. Extensions of the results to location-scale families, multivariate distributions, and principal surfaces are also discussed.
- Published
- 2015
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17. The cell matrix closest to a given Euclidean distance matrix
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Hiroshi Kurata and Pablo Tarazaga
- Subjects
Numerical Analysis ,Algebra and Number Theory ,Hollow matrix ,Block matrix ,Single-entry matrix ,Quantitative Biology::Cell Behavior ,Combinatorics ,Distance matrix ,Matrix function ,Discrete Mathematics and Combinatorics ,Symmetric matrix ,Physics::Atomic Physics ,Geometry and Topology ,Nonnegative matrix ,Centrosymmetric matrix ,Mathematics - Abstract
Cell matrix introduced by Jaklic and Modic [6] is a special Euclidean distance matrix (EDM) that has a quite attractive and simple structure. It is of interest to approximate an EDM by a cell matrix. In this paper, we consider the problem of finding the cell matrix that is closest to a given EDM with respect to the Frobenius norm. The majorization ordering of the eigenvalues of a cell matrix is also discussed.
- Published
- 2015
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18. Service costs and economic welfare
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Hiroshi Kurata
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Service (business) ,Marginal cost ,media_common.quotation_subject ,General Business, Management and Accounting ,Microeconomics ,Cost reduction ,Incentive ,Economics ,Economic welfare ,General Economics, Econometrics and Finance ,Welfare ,health care economics and organizations ,Industrial organization ,media_common - Abstract
This study examines the effects of service cost reduction on a “service-with-location” industry from a welfare perspective. We consider the situation where firms decide to locate in one of two regions with different region-specific marginal costs in industries with and without entry regulation. We demonstrate that in the entry-regulated industry, service cost reduction is favorable for producers and the overall economy, but it may be unfavorable for consumers. In contrast, in the entry-unregulated industry, service cost reduction is unambiguously favorable for all agents. This result implies that governments have an incentive to implement policies to reduce service costs, and they need formulate policies to protect consumers when service costs are reduced under entry-regulation.
- Published
- 2015
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19. Moore–Penrose inverse of a Euclidean distance matrix
- Author
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Hiroshi Kurata and Ravindra B. Bapat
- Subjects
Numerical Analysis ,Algebra and Number Theory ,Hollow matrix ,High Energy Physics::Phenomenology ,Inverse ,Positive-definite matrix ,Euclidean distance matrix ,Combinatorics ,Schur complement ,Discrete Mathematics and Combinatorics ,Physics::Atomic Physics ,Geometry and Topology ,Laplacian matrix ,Nuclear Experiment ,Laplace operator ,Moore–Penrose pseudoinverse ,Mathematics - Abstract
We obtain expressions for the Moore–Penrose inverse of a Euclidean distance matrix (EDM) that are determined only by the positive semidefinite matrix associated with the EDM. The results complement formulas for the Moore–Penrose inverse of an EDM given in Balaji and Bapat (2007) [2] . A formula for the inverse of a principal submatrix of an EDM is also derived, whose expression uses the Schur complement of the Laplacian of the EDM. As an application, we obtain an expression for the terminal Wiener index of a tree.
- Published
- 2015
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20. Best equivariant estimator of regression coefficients in a seemingly unrelated regression model with known correlation matrix
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Shun Matsuura and Hiroshi Kurata
- Subjects
Statistics and Probability ,Mean squared error ,05 social sciences ,Generalized least squares ,Seemingly unrelated regressions ,Newey–West estimator ,01 natural sciences ,010104 statistics & probability ,0502 economics and business ,Statistics ,Ordinary least squares ,Applied mathematics ,Equivariant map ,050211 marketing ,0101 mathematics ,Invariant estimator ,Linear least squares ,Mathematics - Abstract
This paper derives the best equivariant estimator (BEE) of the regression coefficients of a seemingly unrelated regression model with an elliptically symmetric error. Equivariance with respect to the group of location and scale transformations is considered. We assume that the correlation matrix of the error term is known. Since the correlation matrix is a maximal invariant parameter under the group action, the model treated in this paper is generated as exactly one orbit on the parameter space. It is also shown that the BEE can be viewed as a generalized least squares estimator.
- Published
- 2015
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21. Artificially Low Interest Rates as Export Promotion Policy
- Author
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Hiroshi Kurata and Yasunobu Tomoda
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Economics and Econometrics ,Public economics ,business.industry ,media_common.quotation_subject ,Measures of national income and output ,Rationing ,Monetary economics ,Interest rate ,Promotion (rank) ,Service (economics) ,Economics ,business ,Tertiary sector of the economy ,Welfare ,media_common - Abstract
We reconsider the effects of a policy that sets an artificially low interest rate. Such a policy involves a combination of an interest rate ceiling and a rationing rule that assigns a priority-lending status to export sectors over domestic service sectors. We demonstrate that the policy works as an export-promotion policy, and improves national income. Furthermore, under some conditions, the policy expands the domestic service sector, despite the reduced amount of funds owing to the rationing rule. Finally, the artificially low interest rate improves national welfare.
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- 2015
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22. Characterization of multispherical and block structures of Euclidean distance matrices
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Shun Matsuura and Hiroshi Kurata
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Numerical Analysis ,Pure mathematics ,Algebra and Number Theory ,Generalization ,High Energy Physics::Phenomenology ,Block (permutation group theory) ,Positive-definite matrix ,Characterization (mathematics) ,Euclidean distance matrix ,Combinatorics ,Euclidean distance ,Discrete Mathematics and Combinatorics ,Physics::Atomic Physics ,Geometry and Topology ,Nuclear Experiment ,Focus (optics) ,Mathematics - Abstract
This paper presents some new characterizations of Euclidean distance matrices (EDMs) of special structures. More specifically, we discuss multispherical and block-structured EDMs, each of which can be viewed as a generalization of spherical EDM. We focus on a well-known inequality that characterizes spherical EDMs and extend it to the sets of multispherical and block-structured EDMs. Some related results are also presented.
- Published
- 2013
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23. Principal points for an allometric extension model
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Shun Matsuura and Hiroshi Kurata
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Statistics and Probability ,Combinatorics ,Pure mathematics ,Cardinal point ,Distribution (mathematics) ,Mean squared error ,Principal component analysis ,Context (language use) ,Extension (predicate logic) ,Statistics, Probability and Uncertainty ,Space (mathematics) ,Linear subspace ,Mathematics - Abstract
A set of \(n\)-principal points of a \(p\)-dimensional distribution is an optimal \(n\)-point-approximation of the distribution in terms of a squared error loss. It is in general difficult to derive an explicit expression of principal points. Hence, we may have to search the whole space \(R^p\) for \(n\)-principal points. Many efforts have been devoted to establish results that specify a linear subspace in which principal points lie. However, the previous studies focused on elliptically symmetric distributions and location mixtures of spherically symmetric distributions, which may not be suitable to many practical situations. In this paper, we deal with a mixture of elliptically symmetric distributions that form an allometric extension model, which has been widely used in the context of principal component analysis. We give conditions under which principal points lie in the linear subspace spanned by the first several principal components.
- Published
- 2013
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24. Covariance structure associated with an equality between two general ridge estimators
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Koji Tsukuda and Hiroshi Kurata
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Statistics and Probability ,Gauss markov model ,Covariance matrix ,Estimator ,Perturbation (astronomy) ,Mathematics - Statistics Theory ,Statistics Theory (math.ST) ,Best linear unbiased prediction ,Covariance ,Residual ,Ordinary least squares ,FOS: Mathematics ,Applied mathematics ,Statistics, Probability and Uncertainty ,Mathematics - Abstract
In a general linear model, this paper derives a necessary and sufficient condition under which two general ridge estimators coincide with each other. The condition is given as a structure of the dispersion matrix of the error term. Since the class of estimators considered here contains linear unbiased estimators such as the ordinary least squares estimator and the best linear unbiased estimator, our result can be viewed as a generalization of the well-known theorems on the equality between these two estimators, which have been fully studied in the literature. Two related problems are also considered: equality between two residual sums of squares, and classification of dispersion matrices by a perturbation approach., Comment: 16 pages. This is a pre-print of an article published in Statistical Papers. The final authenticated version is available online at: https://doi.org/10.1007/s00362-017-0975-8
- Published
- 2017
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25. Definition and Properties ofm-Dimensionaln-Principal Points
- Author
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Hiroshi Kurata and Shun Matsuura
- Subjects
Statistics and Probability ,Set (abstract data type) ,Combinatorics ,Cardinal point ,Generalization ,Dimension (graph theory) ,Principal component analysis ,Linear subspace ,Distribution (differential geometry) ,Mathematics - Abstract
In this article, we introduce the notion of “m-dimensional n-principal points,” which is a generalization of the notion of n-principal points. A set of m-dimensional n-principal points of a distribution is defined as a set of n points that optimally represents the distribution in terms of mean squared distance subject to the condition that the dimension of the linear subspace spanned by the n points is at most m. Its properties and connections to principal components are investigated for elliptically symmetric distributions and a location mixture of spherically symmetric distributions.
- Published
- 2013
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26. Optimal Correlation Preserving Linear Predictors of Factor Scores in Factor Analysis
- Author
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Hiroshi Kurata and Kazumasa Mori
- Subjects
Correlation ,Factor (chord) ,Statistics ,Linear prediction ,Mean squared error matrix ,Risk matrix ,Mathematics - Abstract
This paper studies a prediction problem of factor scores with correlationpreserving linear predictors. We deal with three new risk functions that are obtained by modifying some typical risk functions in the literature, and derive optimal correlation-preserving linear predictors with respect to them. A necessary and sufficient condition for an identical equality among the predictors to hold is also derived.
- Published
- 2013
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27. Moore-Penrose inverse of a hollow symmetric matrix and a predistance matrix
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Hiroshi Kurata and Ravindra B. Bapat
- Subjects
Algebra and Number Theory ,Hamiltonian matrix ,Hollow matrix ,Euclidean distance matrix ,010102 general mathematics ,010103 numerical & computational mathematics ,Single-entry matrix ,hollow matrix ,01 natural sciences ,Square matrix ,Moore-Penrose inverse ,Predistance matrix ,Positive semidefinite matrix ,Matrix function ,QA1-939 ,Symmetric matrix ,Geometry and Topology ,Nonnegative matrix ,0101 mathematics ,Centrosymmetric matrix ,Laplacian matrix ,Tree ,Mathematics ,Mathematical physics - Abstract
By a hollow symmetric matrix we mean a symmetric matrix with zero diagonal elements. The notion contains those of predistance matrix and Euclidean distance matrix as its special cases. By a centered symmetric matrix we mean a symmetric matrix with zero row (and hence column) sums. There is a one-toone correspondence between the classes of hollow symmetric matrices and centered symmetric matrices, and thus with any hollow symmetric matrix D we may associate a centered symmetric matrix B, and vice versa. This correspondence extends a similar correspondence between Euclidean distance matrices and positive semidefinite matrices with zero row and column sums.We show that if B has rank r, then the corresponding D must have rank r, r + 1 or r + 2. We give a complete characterization of the three cases.We obtain formulas for the Moore-Penrose inverse D+ in terms of B+, extending formulas obtained in Kurata and Bapat (Linear Algebra and Its Applications, 2015). If D is the distance matrix of a weighted tree with the sum of the weights being zero, then B+ turns out to be the Laplacian of the tree, and the formula for D+ extends a well-known formula due to Graham and Lovász for the inverse of the distance matrix of a tree.
- Published
- 2016
28. Free Trade Agreement and Vertical Trade with a Manufacturing Base
- Author
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Akihiko Yanase, Yasushi Kawabata, and Hiroshi Kurata
- Subjects
business.industry ,media_common.quotation_subject ,Geography, Planning and Development ,Tariff ,International trade ,International economics ,Development ,Intermediate good ,Free trade agreement ,Final good ,International free trade agreement ,Economics ,Production (economics) ,business ,Welfare ,media_common - Abstract
We examine the effects of free trade agreement (FTA) on tariffs and welfare in a three-country model with vertical trade, where an FTA is formed between a country exporting a final good whose production involves using an intermediate good, and a country exporting the intermediate good in exchange for the final good. We demonstrate that the FTA reduces its member country's external tariff, whereas it raises the non-member country's tariff. The non-member country unambiguously becomes better off. In contrast, the FTA may or may not make its member countries better off. This implies that the formation of an FTA may not always be Pareto-improving.
- Published
- 2012
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29. Majorization for the eigenvalues of Euclidean distance matrices
- Author
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Hiroshi Kurata and Pablo Tarazaga
- Subjects
Numerical Analysis ,Matrix differential equation ,Algebra and Number Theory ,Orthogonal group ,Euclidean distance matrix ,Eigenvalues ,Positive-definite matrix ,15A57 ,Combinatorics ,Euclidean distance ,Positive semidefinite matrix ,Spectrum of a matrix ,Discrete Mathematics and Combinatorics ,Majorization ,Geometry and Topology ,Eigenvalues and eigenvectors ,Mathematics - Abstract
This paper investigates the relation between the eigenvalues of a Euclidean distance matrix (EDM) and those of the corresponding positive semidefinite matrix. More precisely, let D 1 and D 2 be two EDMs and let B 1 and B 2 be the corresponding positive semidefinite matrices such that D i = κ ( B i ) ( i = 1 , 2 ) . In this paper, when the eigenvalues of B 1 majorizes those of B 2 , a condition under which the eigenvalues of D 1 majorizes those of D 2 is derived.
- Published
- 2012
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30. Linear Subspace Spanned by Principal Points of a Mixture of Spherically Symmetric Distributions
- Author
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Dingxi Qiu and Hiroshi Kurata
- Subjects
Statistics and Probability ,Symmetric function ,Combinatorics ,Pure mathematics ,Distribution (mathematics) ,Cardinal point ,Integer ,Covariance matrix ,Linear discriminant analysis ,Linear subspace ,Eigenvalues and eigenvectors ,Mathematics - Abstract
For each positive integer k, a set of k-principal points of a distribution is the set of k points that optimally represent the distribution in terms of mean squared distance. However, explicit form of k-principal points is often difficult to obtain. Hence a theorem established by Tarpey et al. (1995) has been influential in the literature, which states that when the distribution is elliptically symmetric, any set of k-principal points is in the linear subspace spanned by some principal eigenvectors of the covariance matrix. This theorem is called a “principal subspace theorem”. Recently, Yamamoto and Shinozaki (2000b) derived a principal subspace theorem for 2-principal points of a location mixture of spherically symmetric distributions. In their article, the ratio of mixture was set to be equal. This article derives a further result by considering a location mixture with unequal mixture ratio.
- Published
- 2011
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31. Market Size and Firm Location in a Service Industry
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Hiroshi Kurata, Takao Ohkawa, and Makoto Okamura
- Subjects
Factor market ,Labour economics ,business.industry ,media_common.quotation_subject ,Geography, Planning and Development ,Market size ,Nonmarket forces ,Social Welfare ,Development ,Market economy ,Market analysis ,Economics ,business ,Welfare ,Tertiary sector of the economy ,media_common - Abstract
This paper investigates the welfare effects of firm location in a service industry. We consider the situation where firms determine their locations in either of two regions with a difference in market size. From the viewpoint of the consumers' welfare, there are too few firms in the large market and too many in the small market. However, from the viewpoint of the producers' and social welfare, the opposite is true. Further, an increase in the difference in market size is unambiguously unfavorable for the producers. On the other hand, such an increase is favorable for the consumers and the economy as a whole.
- Published
- 2011
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32. Vertical trade and free trade agreements
- Author
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Yasushi Kawabata, Akihiko Yanase, and Hiroshi Kurata
- Subjects
Economic integration ,Economics and Econometrics ,business.industry ,media_common.quotation_subject ,Tariff ,International trade ,International economics ,Intermediate good ,Final good ,International free trade agreement ,Political Science and International Relations ,Economics ,business ,Trade barrier ,Free trade ,Welfare ,Finance ,media_common - Abstract
We investigate the effects of free trade agreements (FTAs) on tariffs and welfare in vertical trade. We consider a three-country model, where an FTA is formed between a country exporting a final good and a country exporting an intermediate good. The FTA unambiguously leads to a reduction in the member country’s tariff, but may cause the non-member country’s tariff level to increase. In the case, where FTA raises the non-member country’s tariff level, the FTA increases that country’s welfare. In contrast, the FTA may render its member countries better off. This result implies that the formation of an FTA may not always be Pareto-improving.
- Published
- 2010
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33. A principal subspace theorem for 2-principal points of general location mixtures of spherically symmetric distributions
- Author
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Hiroshi Kurata and Shun Matsuura
- Subjects
Statistics and Probability ,Symmetric function ,Set (abstract data type) ,Mean estimation ,Pure mathematics ,Cardinal point ,Probability theory ,Mixed distribution ,Geometry ,Principal subspace ,Statistics, Probability and Uncertainty ,Linear subspace ,Mathematics - Abstract
In this paper, we study 2-principal points of general location mixtures, including finite and infinite mixtures, of spherically symmetric distributions. A theorem is established that clarifies a linear subspace in which any set of 2-principal points exists.
- Published
- 2010
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34. Multispherical Euclidean distance matrices
- Author
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Pablo Tarazaga and Hiroshi Kurata
- Subjects
Block structure ,Numerical Analysis ,Algebra and Number Theory ,Euclidean distance matrix ,Center (group theory) ,Positive-definite matrix ,positive semidefinite matrix ,Euclidean distance ,Combinatorics ,Hyperplane ,Distance from a point to a plane ,Discrete Mathematics and Combinatorics ,Geometry and Topology ,Representation (mathematics) ,Distance matrices in phylogeny ,Mathematics - Abstract
In this paper we introduce new necessary and sufficient conditions for an Euclidean distance matrix to be multispherical. The class of multispherical distance matrices studied in this paper contains not only most of the matrices studied by Hayden et al. (1996) 2 , but also many other multispherical structures that do not satisfy the conditions in Hayden et al. (1996) 2 . We also study the information provided by the origin of coordinates when it is placed at the center of the spheres and the origin representation property is satisfied. These vectors associated with the origin of coordinates generate a number of supporting hyperplanes for a family of multispherical matrices and also describe part of the null space of the corresponding distance matrices.
- Published
- 2010
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35. Non-expected utility maximizers behave as if expected utility maximizers: An experimental test
- Author
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Makoto Okamura, Hiroshi Izawa, and Hiroshi Kurata
- Subjects
Economics and Econometrics ,Isoelastic utility ,Econometrics ,Subjective expected utility ,Von Neumann–Morgenstern utility theorem ,Mathematical economics ,Expected utility hypothesis ,Mathematics - Abstract
We investigate the behaviors of subjects who either do or do not adhere to the expected utility theory using the Becker–DeGroot–Marschak (BDM) method. We directly examine the validity of the expected utility theory in order to distinguish subjects into two groups: those who adhere to the expected utility theory (expected utility maximizers) and those who do not adhere to it (non-expected utility maximizers), and then execute the BDM experiment in the both groups. We find that the differences in the stated prices between the expected and non-expected utility maximizers are not significant. This result implies practical usefulness for the BDM method.
- Published
- 2009
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36. A theorem on the covariance matrix of a generalized least squares estimator under an elliptically symmetric error
- Author
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Hiroshi Kurata
- Subjects
Statistics and Probability ,Covariance matrix ,Multivariate normal distribution ,Generalized least squares ,Covariance ,Newey–West estimator ,Estimation of covariance matrices ,Statistics ,Statistics::Methodology ,Applied mathematics ,Statistics, Probability and Uncertainty ,Linear least squares ,Mathematics ,Variance function - Abstract
In a general linear regression model, a generalized least squares estimator (GLSE) is widely employed as an estimator of regression coefficient. The efficiency of the GLSE is usually measured by its covariance (or risk) matrix. In this paper, it is shown that the covariance matrix remains the same as long as the distribution of the error term is elliptically symmetric. This implies that every efficiency result obtained under normal distribution assumption is still valid under elliptical symmetry. An application to a heteroscedastic linear model is also illustrated.
- Published
- 2009
- Full Text
- View/download PDF
37. Location choice, competition, and welfare in non-tradable service FDI
- Author
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Hiroshi Kurata, Takao Ohkawa, and Makoto Okamura
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Microeconomics ,Competition (economics) ,Economics and Econometrics ,Host country ,Demand curve ,Service (economics) ,media_common.quotation_subject ,Economics ,Foreign direct investment ,Discount points ,Welfare ,Finance ,media_common - Abstract
We investigate whether non-tradable service FDI is efficient from a welfare point of view. A fixed number of firms strategically decide which markets to locate in and then compete in quasi-Cournot fashion. Considering firm location in two symmetric markets, non-tradable service FDI may or may not be efficient for the source country, depending on the total number of firms, competition in markets and the curvature of the demand function. In contrast, non-tradable service FDI is always efficient for the host country and the overall economy. This implies that any policy that affects firm location between two symmetric markets will not be beneficial from a welfare viewpoint.
- Published
- 2009
- Full Text
- View/download PDF
38. The prevalence of periodontopathogenic bacteria in saliva is linked to periodontal health status and oral malodour
- Author
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Shuji Awano, Tadamichi Takehara, Hiroshi Kurata, Toshihiro Ansai, and Akihiro Yoshida
- Subjects
Adult ,Male ,Microbiology (medical) ,Saliva ,Gingival and periodontal pocket ,Bleeding on probing ,Dentistry ,Microbiology ,Prevotella nigrescens ,Tongue ,stomatognathic system ,Oral and maxillofacial pathology ,Humans ,Medicine ,Periodontal Probing ,Periodontal Diseases ,Bacteria ,biology ,business.industry ,Prevotella intermedia ,Treponema denticola ,General Medicine ,Middle Aged ,biology.organism_classification ,medicine.disease ,Odorants ,Female ,medicine.symptom ,business - Abstract
This study investigated whether an improvement in periodontal health resulted in changes in the prevalence of periodontopathogenic bacteria in saliva and tongue coatings and a reduction in volatile sulfur compounds (VSCs: H2S and CH3SH) linked to oral malodour. The subjects were 35 patients who visited the breath odour clinic of Kyushu Dental College, Japan. Their mean age was 51.2±18.3 years (mean±sd). A clinical examination performed at baseline and 2 months after periodontal treatment assessed VSCs in mouth air using gas chromatography, periodontal probing depth and bleeding on probing (BOP) in all subjects; saliva and tongue coatings were also collected. Genomic DNA was isolated from the samples, and the proportions of five periodontopathogenic bacteria (Porphyromonas gingivalis, Tannerella forsythensis, Treponema denticola, Prevotella intermedia and Prevotella nigrescens) were investigated using quantitative real-time PCR. The subjects were classified into four groups based on the presence of a periodontal pocket of more than 4 mm (PD) and VSCs above the organoleptic threshold level (VSCT) as follows: –PD/–VSCT group, subjects without PD or VSCT; –PD/+VSCT group, those without PD but with VSCT; +PD/–VSCT group, those with PD but without VSCT; and +PD/+VSCT group, those with PD and VSCT. Although the mean PD values in the +PD/–VSCT and +PD/+VSCT groups, BOP in the +PD/+VSCT group, and H2S and CH3SH concentrations in the –PD/+VSCT and +PD/+VSCT groups were greater than in the other groups at baseline, we found no significant difference among the four groups after periodontal treatment. The proportion of periodontopathogenic bacteria in saliva was higher in the +PD/–VSCT and +PD/+VSCT groups than in the –PD/–VSCT and –PD/+VSCT groups at baseline and after treatment, but the proportions of bacteria in saliva after treatment were reduced compared to the baseline. Furthermore, the differences in the proportions of the five target bacteria in the tongue coating were not as apparent as those in saliva at baseline or after treatment. The prevalence of periodontopathogenic bacteria in saliva may reflect periodontal health status and influence VSC levels in mouth air.
- Published
- 2008
- Full Text
- View/download PDF
39. Effects of light irradiation on bleaching by a 3.5% hydrogen peroxide solution containing titanium dioxide
- Author
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Hiroshi Kurata, Yoshito Hirai, Junji Kato, Yuki Kumagai, Go Akashi, Tsuyoshi Suemori, Akihiro Igarashi, and Taeko Nakazawa
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Materials science ,Physics and Astronomy (miscellaneous) ,business.industry ,Laser ,law.invention ,chemistry.chemical_compound ,Halogen lamp ,chemistry ,law ,Titanium dioxide ,Halogen ,Photocatalysis ,Optoelectronics ,Irradiation ,Absorption (electromagnetic radiation) ,business ,Hydrogen peroxide ,Instrumentation ,Nuclear chemistry - Abstract
A low-concentration hydrogen peroxide solution containing titanium dioxide as a photocatalyst has attracted attention as a safe office bleaching agent. In this study, the influence of different kinds of light on the bleaching effect of this agent was examined. The bleaching agent was applied to hematoporphyrin-stained paper strips that were then irradiated with a 405-nm diode laser (800 mW/cm2), a halogen lamp (720 mW/cm2), or an LED (835 mW/cm2) for 5 minutes. The color was measured spectrophotometrically before treatment and every 30 seconds thereafter, and the effects of bleaching on the strip were assessed using the CIE 1976 L * a* b* color coordinate system. Of the three different irradiation conditions, 405-nm laser irradiation gave the strongest bleaching effect with 3.5% hydrogen peroxide containing titanium dioxide. The laser provides strong irradiance at 405 nm, which corresponds to the absorption range of the bleaching agent, and consequently the largest effect was obtained.
- Published
- 2008
- Full Text
- View/download PDF
40. Strategic Regional Integration
- Author
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Kjetil Bjorvatn, Hiroshi Kurata, and Nicola D. Coniglio
- Subjects
Competition (economics) ,Oligopoly ,Globalization ,Incentive ,Order (exchange) ,business.industry ,Regional integration ,Economics ,Competitive pressure ,International trade ,Cournot competition ,business ,Industrial organization - Abstract
We analyze the impact of globalization on the incentive to strengthen regional integration. In a simple three-country oligopolistic trade model, we demonstrate that increased external competitive pressure may induce governments, inauenced by producer interests, to lower intra-regional trade costs in order to mitigate the effects of external competition on local businesses.
- Published
- 2016
- Full Text
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41. The amounts of hydroxyl radicals generated by titanium dioxide and 3.5% hydrogen peroxide under 405-nm diode laser irradiation
- Author
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Atsushi Kameyama, Taeko Nakazawa, Hiroshi Kurata, Yoshito Hirai, Junji Kato, K. Sakai, and Go Akashi
- Subjects
Materials science ,Radical ,Condensed Matter Physics ,Laser ,Photochemistry ,Industrial and Manufacturing Engineering ,Atomic and Molecular Physics, and Optics ,law.invention ,Adduct ,chemistry.chemical_compound ,chemistry ,law ,Titanium dioxide ,Photocatalysis ,Irradiation ,Hydrogen peroxide ,Electron paramagnetic resonance ,Instrumentation - Abstract
A new bleaching agent consisting of a titanium dioxide photocatalyst and 3.5% hydrogen peroxide has recently been developed for in-office bleaching and has proven to react well with irradiated light around a wavelength of 400 nm. This study was conducted to evaluate the efficacy of dental bleaching with a 405-nm diode laser irradiation on titanium dioxide and 3.5% hydrogen peroxide by measuring the generation of hydroxyl radicals. The amount of hydroxyl radicals generated from a titanium dioxide and 3.5% hydrogen peroxide irradiated by a 405-nm diode laser were measured using electron spin resonance spin-trapping techniques. The irradiation conditions of the laser were a spot size of 1 mm, output powers of 100, 200, 400 mW, and 600 mW, and irradiation times of 10, 20, 30, and 60 s. Nonirradiated samples were used as controls. DMPO-OH adduct spectra and DMPO-O 2 − adduct spectra were observed when the bleaching agent was irradiated by laser light. The amount of hydroxyl radicals generated changed in accordance with adjustments in the irradiation power and irradiation time. In the nonirradiated controls, hydroxyl radicals were generated in far smaller amounts. The 405-nm diode laser is effective in inducing the generation of hydroxyl radicals and shows promise as a bleaching light source for use in combination with bleaching agents composed of titanium dioxide and low concentrations of hydrogen peroxide.
- Published
- 2007
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42. Effects of Exercise and Nutritional Intervention to Improve Physical Factors Associated with Fracture Risk in Middle-aged and Older Women
- Author
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Hiroshi Kurata, Akira Maeda, Zhen-Bo Cao, Hidetsugu Nishizono, and Norihiro Shima
- Subjects
Fracture risk ,medicine.medical_specialty ,Physical medicine and rehabilitation ,business.industry ,Intervention (counseling) ,Physical therapy ,medicine ,business - Published
- 2007
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43. Foreign equity caps under two types of competition: Bertrand and Cournot
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Hiroshi Kurata
- Subjects
jel:F1 ,Foreign equity caps Cournot competition Bertrand competiton Product differentiation - Abstract
This paper explores foreign equity caps for international joint ventures under different types of competition, i.e., Bertrand and Cournot competition, with product differentiation. We demonstrate that government sets the foreign equity cap at a laxer level under Cournot competition than under Bertrand competition. This result illustrates that the possibility of international joint ventures weakens government's ability to affect firm behavior through the implementation of foreign equity caps.
- Published
- 2007
44. A Propensity Score Adjustment for Multiple Group Structural Equation Modeling
- Author
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Hiroshi Kurata, Takahiro Hoshino, and Kazuo Shigemasu
- Subjects
Delta method ,Matching (statistics) ,Average treatment effect ,Applied Mathematics ,Statistics ,Covariate ,Propensity score matching ,Econometrics ,Estimator ,Latent variable ,General Psychology ,Structural equation modeling ,Mathematics - Abstract
In the behavioral and social sciences, quasi-experimental and observational studies are used due to the difficulty achieving a random assignment. However, the estimation of differences between groups in observational studies frequently suffers from bias due to differences in the distributions of covariates. To estimate average treatment effects when the treatment variable is binary, Rosenbaum and Rubin (1983a) proposed adjustment methods for pretreatment variables using the propensity score. However, these studies were interested only in estimating the average causal effect and/or marginal means. In the behavioral and social sciences, a general estimation method is required to estimate parameters in multiple group structural equation modeling where the differences of covariates are adjusted. We show that a Horvitz-Thompson-type estimator, propensity score weighted M estimator (PWME) is consistent, even when we use estimated propensity scores, and the asymptotic variance of the PWME is shown to be less than that with true propensity scores. Furthermore, we show that the asymptotic distribution of the propensity score weighted statistic under a null hypothesis is a weighted sum of independent χ 1 2 variables. We show the method can compare latent variable means with covariates adjusted using propensity scores, which was not feasible by previous methods. We also apply the proposed method for correlated longitudinal binary responses with informative dropout using data from the Longitudinal Study of Aging (LSOA). The results of a simulation study indicate that the proposed estimation method is more robust than the maximum likelihood (ML) estimation method, in that PWME does not require the knowledge of the relationships among dependent variables and covariates.
- Published
- 2006
- Full Text
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45. The relationship between court surface and tactics in tennis using a computerized scorebook
- Author
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Mitsuo Kodama, Akira Maeda, Hiroshi Kurata, Hidetsugu Nishizono, Hiroo Takahashi, and Tomohito Wada
- Subjects
Point (typography) ,Observer (quantum physics) ,business.industry ,Shot (filmmaking) ,05 social sciences ,Physical Therapy, Sports Therapy and Rehabilitation ,030229 sport sciences ,Time duration ,050105 experimental psychology ,03 medical and health sciences ,0302 clinical medicine ,0501 psychology and cognitive sciences ,Orthopedics and Sports Medicine ,Computer vision ,Artificial intelligence ,business ,Psychology ,Simulation - Abstract
The purpose of this study was to use a newly developed computerised scorebook for tennis in order to clarify the characteristics of tennis tactics used on specific court surfaces. The authors developed a computerised scorebook for tennis that calculates the time duration of shots, points, and the time between points. Data were collected from matches played by male Japanese intercollegiate players. A total of 97 points were observed. Two observers (A, B) were recruited for recording matches using the scorebook. The mean error of observer A was 0.003±0.05 s, while the mean error of observer B was 0.02±0.10 s.The computerised scorebook for tennis was used to collect data for clarifying the characteristics of tennis tactics used on specific court surfaces. Forty-one matches from the Grand Slam tournaments held in 2003 and 2004 were analyzed. The scorebook recorded the final shot of each point, the result of each point, and the time duration of each shot. The final shots were categorised into the following 5 g...
- Published
- 2006
- Full Text
- View/download PDF
46. The importance of scores for game-winning in tennis
- Author
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Hiroo Takahashi, Akira Maeda, Hidetsugu Nishizono, and Hiroshi Kurata
- Subjects
Scoring system ,Multimedia ,Statistics ,Victory ,Psychology ,computer.software_genre ,Discount points ,computer - Abstract
Tennis has a peculiar scoring system. The purpose of this study was clarify the importance of counting one game in tennis matches by studying data from actual games, comprising 42 men's singles matches (907 games) during the Kyushu collegiate tennis championships held in 1997 and 1998. The main criterion for the analysis was the relationship between point-winning at each score and game-winning. It was found that (1) the rate of point-winning by game-winning players was 67.0%, and that the rate of point-winning by opponents was 33.0%. The game-winning players obtained 2/3 of all points. Furthermore (2), the rate of point-winning by players with a leading score was comparatively high at the time of either leading, such as in an up count or a down count, as well as when there was a difference in points at game-point. In particular, the rate of point-winning by game-winning players was significantly high on 0-15 and 15-30. (3) At scores of 30-30 and deuce (i.e. even count), the rate of point-winning by game-winning players was significantly high. These scores led an even count to game-point. These scores also showed a high frequency, and were the key to winning the game. These results suggest that scores of 30-30 and deuce are keys to game-winning, when gaining one point can lead to victory.
- Published
- 2006
- Full Text
- View/download PDF
47. The relationship between point-winning rate and techniques in tennis: an analysis based on regional collegiate championships in Japan
- Author
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Akira Maeda, Hiroshi Kurata, Hidetsugu Nishizono, and Hiroo Takahashi
- Subjects
Match analysis ,Operations research ,Computer science ,Point (geometry) - Published
- 2006
- Full Text
- View/download PDF
48. One-sided tests for independence of seemingly unrelated regression equations
- Author
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Hiroshi Kurata
- Subjects
Statistics and Probability ,Numerical Analysis ,Multivariate analysis ,Alternative hypothesis ,Invariance ,Regression analysis ,Independence ,Invariant (physics) ,Seemingly unrelated regressions ,One sided ,Statistics ,Applied mathematics ,Seemingly unrelated regression model ,Statistics, Probability and Uncertainty ,One-sided hypothesis ,Locally most mean powerful test ,Power function ,Mathematics ,Statistical hypothesis testing - Abstract
In a seemingly unrelated regression model with p(⩾2) equations, this paper considers the problem of testing independence of equations against a one-sided alternative hypothesis. The power functions of invariant tests are evaluated and the locally most mean powerful invariant test is obtained.
- Published
- 2004
- Full Text
- View/download PDF
49. Foreign equity caps for international joint ventures
- Author
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Yasunobu Tomoda and Hiroshi Kurata
- Subjects
jel:F1 ,jel:F2 - Abstract
We analyze foreign equity caps for international joint ventures. We develop a partial equilibrium model in which foreign equity caps are determined endogenously and find an interesting property, named a welfare indifference property i.e., maximization of domestic welfare and that of world welfare are indifferent for the host government. This property also implies that the government is indifferent to the distribution of a JV's profit.
- Published
- 2004
50. A Maximal Extension of the Gauss–Markov Theorem and Its Nonlinear Version
- Author
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Takeaki Kariya and Hiroshi Kurata
- Subjects
Statistics and Probability ,Numerical Analysis ,Class (set theory) ,Location parameter ,Non linearite ,Mathematical analysis ,Extension (predicate logic) ,nonlinear versions of Gauss–Markov theorem ,generalized least squares estimator ,Term (time) ,Gauss–Markov theorem ,Nonlinear system ,Applied mathematics ,Statistical analysis ,location-equivariant estimator ,elliptically symmetric distribution ,Statistics, Probability and Uncertainty ,Mathematics - Abstract
In this paper, first we make a maximal extension of the well-known Gauss–Markov Theorem (GMT) in its linear framework. In particular, the maximal class of distributions of error term for which the GMT holds is derived. Second, we establish a nonlinear version of the maximal GMT and describe some interesting families of distributions of error term for which the nonlinear GMT holds.
- Published
- 2002
- Full Text
- View/download PDF
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