論文 - 加茂　憲一

Nonlinear oscillations of fourth order quasilinear ordinary differential equations

K. Kamo, H. Usami

ACTA MATHEMATICA HUNGARICA ( SPRINGER )  132 ( 3 ) 207 - 222  2011年08月  [査読有り]

担当区分：   筆頭著者  , 責任著者

　概要を見る

We consider fourth order quasilinear ordinary differential equations. Firstly, we classify positive solutions into four types according to their asymptotic properties. Then we derive existence theorems of positive solutions belonging to each type. Using these results, we can obtain an oscillation criterion, which is our main objective. Moreover, applying such criteria for ordinary differential equations to binary elliptic systems, we establish nonexistence theorems for positive solutions.

DOI

A dosimetry study of the Oncoseed 6711 using glass rod dosimeters and EGS5 Monte Carlo code in a geometry lacking radiation equilibrium scatter conditions

Kenichi Tanaka, Kunihiko Tateoka, Osamu Asanuma, Ken-ichi Kamo, Gerard Bengua, Kaori Sato, Toshikazu Ueda, Hiromitsu Takeda, Masaru Takagi, Masato Hareyama, Jun Takada

MEDICAL PHYSICS ( AMER ASSOC PHYSICISTS MEDICINE AMER INST PHYSICS )  38 ( 6 ) 3069 - 3076  2011年06月  [査読有り]

　概要を見る

Purpose: The aim of this study was to develop a dose calculation method which is applicable to the interseed attenuation and the geometry lacking the equilibrium radiation scatter conditions in brachytherapy. Methods: The dose obtained from measurement with a radiophotoluminescent glass rod dosimeter (GRD) was compared to the dose calculated with the Monte Carlo (MC) code "EGS5," using the (125)I source structure detailed in by Kennedy 1 The GRDs were irradiated with (125)I Oncoseed 6711 in a human head phantom. The phantom was a cylinder made of 2 mm thick PMMA with a diameter of 18 cm and length of 16 cm. Some of the GRD positions were so close to the phantom surface that the backscatter margin was less than 5 cm, insufficient for photons. Results: The EGS5 simulations were found to reproduce the relative dose distributions as measured with the GRDs to within 25% uncertainty in the geometry lacking the equilibrium radiation scatter conditions. The absolute value of the GRD measurement agreed with the American Association of Physicist in Medicine Task Group No 43 Updated Protocol (AAPM-TG43U1) formalism to within 3% of the reference point (r = 1 cm, theta = 90 degrees), where the TG43U1 is especially reliable because of the abundant data accumulation in composing the formalism. The factor to normalize the measured or calculated dose to the TG43U1 estimate at the reference point was evaluated to be 0.97 for the GRD measurement and 1.8 for the MC calculation, which uses the integration of the apparent activity with the time as the amount of disintegration during the irradiation. Also, F(r,theta) and g(r) estimated by this calculation method were consistent with those proposed in the TG43U1. Conclusions: The results of this investigation support the validity of both the MC calculation method and GRD measurement in this study as well as the TG-43U1 formalism. Also, this calculation is applicable to interseed attenuation and the geometry lacking the equilibrium radiation scatter.(C) 2011 American Association of Physicists in Medicine. [DOI: 10.1118/1.3590370]

DOI

Second-order bias-corrected AIC in multivariate normal linear models under non-normality

Hirokazu Yanagihara, Ken-Ichi Kamo, Tetsuji Tonda

CANADIAN JOURNAL OF STATISTICS-REVUE CANADIENNE DE STATISTIQUE ( WILEY-BLACKWELL PUBLISHING, INC )  39 ( 1 ) 126 - 146  2011年03月  [査読有り]

　概要を見る

This paper deals with a bias correction of Akaike's information criterion (AIC) for selecting variables in multivariate normal linear regression models when the true distribution of observation is an unknown non-normal distribution. It is well known that the bias of AIC is O(1), and there are a number of the first-order bias-corrected AICs which improve the bias to O(n(-1)), where n is the sample size. A new information criterion is proposed by slightly adjusting the first-order bias-corrected AIC. Although the adjustment is achieved by merely using constant coefficients, the bias of the new criterion is reduced to O(n(-2)). Then, a variance of the new criterion is also improved. Through numerical experiments, we verify that our criterion is superior to others. The Canadian Journal of Statistics 39: 126-146; 2011 (C) 2011 Statistical Society of Canada

DOI

Study on the effect of measles control programmes on periodic structures of disease epidemics in a large Chinese city

T. Luo, A. Sumi, D. Zhou, K. Kamo, B. Yu, D. Zhao, K. Mise, N. Kobayashi

EPIDEMIOLOGY AND INFECTION ( CAMBRIDGE UNIV PRESS )  139 ( 2 ) 257 - 264  2011年02月  [査読有り]

　概要を見る

Measles is regarded as a disease that can be eliminated by vaccination; however, disease epidemics still occur in Wuhan, China. This study explored the effect of measles control programmes on the periodic structure of disease epidemics in Wuhan. The monthly reported measles incidence from 1953 to 2008 was divided into pre-vaccine range (1953-1965) and post-vaccine range (1966-2008). For the incidence in each range, spectral analysis was conducted and power spectral density (PSD) was obtained. In PSD for the pre-vaccine range, the most dominant spectral line was observed at a 2.0-year period, as in the case of Japan. It was confirmed that spectral lines of periodic modes longer than a 1-year cycle of the incidence rates behave in response to the introduction of measles control programmes. The investigation of periodic structures of measles epidemics will contribute to effective measles control programmes in Wuhan.

DOI

Cancer Incidence and Incidence Rates in Japan in 2005: Based on Data from 12 Population-based Cancer Registries in the Monitoring of Cancer Incidence in Japan (MCIJ) Project

Tomohiro Matsuda, Tomomi Marugame, Ken-ichi Kamo, Kota Katanoda, Wakiko Ajiki, Tomotaka Sobue

JAPANESE JOURNAL OF CLINICAL ONCOLOGY ( OXFORD UNIV PRESS )  41 ( 1 ) 139 - 147  2011年01月  [査読有り]

　概要を見る

The Japan Cancer Surveillance Research Group estimated the cancer incidence in 2005 as part of the Monitoring of Cancer Incidence in Japan (MCIJ) project, on the basis of data collected from 12 of 30 population-based cancer registries. The total number of incidences in Japan for 2005 was estimated as 646 802 (C00-C96). The leading cancer site was the stomach for men and the breast for women. Age-standardized incidence rates remained almost the same level as the previous 2 years.

DOI

Time Series Analysis of Incidence Data of Influenza in Japan

Ayako Sumi, Ken-ichi Kamo, Norio Ohtomo, Keiji Mise, Nobumichi Kobayashi

JOURNAL OF EPIDEMIOLOGY ( JAPAN EPIDEMIOLOGICAL ASSOC )  21 ( 1 ) 21 - 29  2011年01月  [査読有り]

　概要を見る

Background: Much effort has been expended on interpreting the mechanism of influenza epidemics, so as to better predict them. In addition to the obvious annual cycle of influenza epidemics, longer-term incidence patterns are present. These so-called interepidemic periods have long been a focus of epidemiology. However, there has been less investigation of the interepidemic period of influenza epidemics. In the present study, we used spectral analysis of influenza morbidity records to indentify the interepidemic period of influenza epidemics in Japan. Methods: We used time series data of the monthly incidence of influenza in Japan from January 1948 through December 1998. To evaluate the incidence data, we conducted maximum entropy method (MEM) spectral analysis, which is useful in investigating the periodicities of shorter time series, such as that of the incidence data used in the present study. We also conducted a segment time series analysis and obtained a 3-dimensional spectral array. Results: Based on the results of power spectral density (PSD) obtained from MEM spectral analysis, we identified 3 periodic modes as the interepidemic periods of the incidence data. Segment time series analysis revealed that the amount of amplitude of the interepidemic periods increased during the occurrence of influenza pandemics and decreased when vaccine programs were introduced. Conclusions: The findings suggest that the temporal behavior of the interepidemic periods of influenza epidemics is correlated with the magnitude of cross-reactive immune responses.

DOI

日本におけるがん罹患率の動向

邱冬梅, 加茂憲一, 坂本なほ子

統計数理 ( 統計数理研究所 )  59 ( 2 ) 193 - 204  2011年  [査読有り]

　概要を見る

要旨ありがん統計データおよびその解析研究ノート

CiNii

年齢－時代平面上における癌死亡リスクの視覚化

加茂憲一, 冨田哲治, 佐藤健一

統計数理 ( 統計数理研究所 )  59 ( 2 ) 217 - 238  2011年  [査読有り]

担当区分：   筆頭著者  , 責任著者

　概要を見る

要旨ありがん統計データおよびその解析研究ノート

CiNii

Cancer Incidence and Incidence Rates in Japan in 2004: Based on Data from 14 Population-based Cancer Registries in the Monitoring of Cancer Incidence in Japan (MCIJ) Project

Tomohiro Matsuda, Tomomi Marugame, Ken-ichi Kamo, Kota Katanoda, Wakiko Ajiki, Tomotaka Sobue

JAPANESE JOURNAL OF CLINICAL ONCOLOGY ( OXFORD UNIV PRESS )  40 ( 12 ) 1192 - 1200  2010年12月  [査読有り]

　概要を見る

The Japan Cancer Surveillance Research Group estimated the cancer incidence in 2004 as part of the Monitoring of Cancer Incidence in Japan (MCIJ) project, on the basis of data collected from 14 of 31 population-based cancer registries. The total number of incidences in Japan for 2004 was estimated as 623 275 (C00-C96). The leading cancer site according to the crude and age-standardized incidence rates was the stomach for men and breast for women. The apparent increase in age-standardized incidence rates in 2003 was calmed down in 2004.

DOI

Characterization of slowly decaying positive solutions of second-order quasilinear ordinary differential equations with sub-homogeneity

Ken-ichi Kamo, Hiroyuki Usami

BULLETIN OF THE LONDON MATHEMATICAL SOCIETY ( OXFORD UNIV PRESS )  42 ( 3 ) 420 - 428  2010年06月  [査読有り]

担当区分：   筆頭著者  , 責任著者

　概要を見る

We consider quasilinear ordinary differential equations with sub-homogeneity near infinity. A necessary and sufficient condition is obtained for the equations to have slowly decaying positive solutions. Asymptotic forms of such positive solutions are established. As an application of these results, we obtain Liouville-type theorems for quasilinear elliptic problems.

DOI

A robust estimation method for a growth curve model with balanced design

K.Satoh, H.Yanagihara, K.Kamo

Advanced in Theory and Applications   3 ( 2 ) 113 - 124  2010年  [査読有り]

担当区分：   最終著者

Estimation of cancer incidence in Japan with an age-period-cohort model

M.Utada, Y, Ohno, M.Soda, K.Kamo

Asian Pacific Journal of Cancer Prevention   11 ( 5 ) 1235 - 1240  2010年  [査読有り]

担当区分：   最終著者

Cancer Incidence and Incidence Rates in Japan in 2003: Based on Data from 13 Population-based Cancer Registries in the Monitoring of Cancer Incidence in Japan (MCIJ) Project

Tomohiro Matsuda, Tomomi Marugame, Ken-ichi Kamo, Kota Katanoda, Wakiko Ajiki, Tomotaka Sobue

JAPANESE JOURNAL OF CLINICAL ONCOLOGY ( OXFORD UNIV PRESS )  39 ( 12 ) 850 - 858  2009年12月  [査読有り]

DOI

2003年データに基づく、生涯がん罹患・死亡リスク推定(Lifetime probability of developing or dying of cancer in 2003)

加茂 憲一, 片野田 耕太, 松田 智大, 丸亀 知美, 味木 和喜子, 祖父江 友孝

日本癌学会総会記事 ( (一社)日本癌学会 )  68回   507 - 507  2009年08月

離散分布の経時測定データにおける線形な変化係数の推測について

佐藤健一, 柳原宏和, 加茂憲一

応用統計学 ( Japanese Society of Applied Statistics )  38 ( 1 ) 19 - 28  2009年  [査読有り]

担当区分：   最終著者

　概要を見る

回帰モデルにおいて，変化係数は時間とともに変化する説明変数の効果を評価でき，視覚的にも理解しやすいために広く利用されるようになってきた．その推定値は固定された時間ごとに近傍データを用いて回帰をすることで容易に得られる．しかしながら，時間についての連続性がないために観測時間を通した曲線としての信頼区間の構成および検定に困難があった．本稿ではSatoh and Yanagihara (2008) で提案された連続分布の経時測定データにおける線形な変化係数に関する推測方法を，成長曲線モデルおよび変量効果モデルとの関連を述べながら，一般化推定方程式を利用し離散分布に適用することを試みる．この手法の利点のひとつとして汎用的なソフトウェアを利用して計算できることが挙げられる．解析例ではロジスティック回帰モデルにおける変化係数の推定を紹介する．

DOI CiNii

Logistic regression model and model selection for estimating the risk of natural disaster

K.Kamo, H.Yanagihara, A.Kato, A.Yoshimoto

Forest Resource Management and Mathematical Modeling ( FORMATH Research Group )  8   137 - 152  2009年  [査読有り]

担当区分：   筆頭著者  , 責任著者

DOI

Positive unbounded solutions of second order quasilinear ordinary differential equations and their application to elliptic problems

Ken-Ichi Kamo, Hiroyuki Usami

Czechoslovak Mathematical Journal   58 ( 4 ) 1153 - 1165  2008年12月  [査読有り]

担当区分：   筆頭著者  , 責任著者

　概要を見る

In this paper we consider positive unbounded solutions of second order quasilinear ordinary differential equations. Our objective is to determine the asymptotic forms of unbounded solutions. An application to exterior Dirichlet problems is also given. © 2008 Mathematical Institute, Academy of Sciences of Czech Republic.

DOI

生命表法による、がん罹患・死亡リスク推定

加茂 憲一, 片野田 耕太, 松田 智大, 丸亀 知美, 味木 和喜子, 祖父江 友孝

日本公衆衛生学会総会抄録集 ( 日本公衆衛生学会 )  67回   223 - 223  2008年10月

Cancer incidence and incidence rates in Japan in 2002: Based on data from 11 population-based cancer registries

Tomohiro Matsuda, Tomomi Marugame, Ken-ichi Kamo, Kota Katanoda, Wakiko Ajiki, Tomotaka Sobue

JAPANESE JOURNAL OF CLINICAL ONCOLOGY ( OXFORD UNIV PRESS )  38 ( 9 ) 641 - 648  2008年09月  [査読有り]

　概要を見る

The number of cancer incidences, crude incidence rates, age-standardized incidence rates in 2002 in Japan are estimated. The estimated total number of incidences was 570 598.

DOI

回帰モデルによるがん罹患数全国推定(Estimate of nation-wide cancer incidence by regression model)

加茂 憲一, 片野田 耕太, 松田 智大, 丸亀 知美, 味木 和喜子, 祖父江 友孝

日本癌学会総会記事 ( (一社)日本癌学会 )  67回   378 - 378  2008年09月