result 1218 件
| JaLCDOI | 10.18926/47029 |
|---|---|
| FullText URL | mfe_36_2_083_089.pdf |
| Author | Watanabe, Tetsushi| Wada, Osami| Koga, Ryuji| Toyota, Yoshitaka| Miyashita, Takuya| |
| Abstract | Suppression of common-mode current is important to achieve electromagnetic compatibility of high-speed and high-density electronic circuits. The authors have focused on the common mode current flowing on a printed circuit board (PCB) to explain the excitation mechanism. A narrow ground pattern in microstrip structure excites common-mode current. In the previous paper, the authors explained the mechanism of common mode generation by means of "current division factor" for simple PCBs. The estimated radiation from a simple PCB agreed well with measured one. In this paper, the authors extend the theory to be applied to generalize ground structure. The validity of the theory is confirmed by comparing the measured radiation and the estimated value using the common-mode model for a test PCB. The estimated radiation agrees well with the measured one within 3 dB up to 900 MHz. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2002-03 |
| Volume | volume36 |
| Issue | issue2 |
| Start Page | 83 |
| End Page | 89 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120003497051 |
| JaLCDOI | 10.18926/AMO/47018 |
|---|---|
| FullText URL | 65_5_347.pdf |
| Author | Mukai, Takashi| Mimura, Hidefumi| Gobara, Hideo| Shimizu, Mitsuharu| Niiya, Harutaka| Kanazawa, Susumu| |
| Abstract | We report herein the case of a 76-year-old woman with autosomal dominant polycystic kidney disease (ADPKD) and chronic renal failure resulting in intractable abdominal distension and anorexia. Computed tomography (CT) showed enlarged and cystic kidneys. We performed transcatheter arterial embolization (TAE) for renal arteries with ethanol. Absolute ethanol with iodinated contrast medium or Lipiodol was delivered into both renal arteries. The patient's low-grade fever subsided in 5 days, and no other complication occurred. The sensation of abdominal distension diminished approximately 1 month after embolization. A progressive decrease in kidney size was observed soon after embolization. The percentage of the decrement of kidney size was approximately 50% after 17 months. These results indicate that renal TAE with ethanol is a safe, cost-effective, and minimally invasive technique to reduce kidney size in symptomatic ADPKD patients. |
| Keywords | autosomal dominant polycystic kidney disease transcatheter arterial embolization ethanol |
| Amo Type | Case Report |
| Publication Title | Acta Medica Okayama |
| Published Date | 2011-10 |
| Volume | volume65 |
| Issue | issue5 |
| Publisher | Okayama University Medical School |
| Start Page | 347 |
| End Page | 351 |
| ISSN | 0386-300X |
| NCID | AA00508441 |
| Content Type | Journal Article |
| language | English |
| Copyright Holders | CopyrightⒸ 2011 by Okayama University Medical School |
| File Version | publisher |
| Refereed | True |
| PubMed ID | 22037273 |
| Web of Science KeyUT | 000296116400010 |
| JaLCDOI | 10.18926/47004 |
|---|---|
| FullText URL | mfe_36_1_107_116.pdf |
| Author | Kanatani, Kenichi| Ohta, Naoya| |
| Abstract | We present a new method for automatically detecting circular objects in images: we detect an osculating circle to an elliptic arc using a Hough transform, iteratively deforming it into an ellipse, removing outlier pixels, and searching for a separate edge. The voting space is restricted to one and two dimensions for efficiency, and special weighting schemes are introduced to enhance the accuracy. We demonstrate the effectiveness of our method using real images. Finally, we apply our method to the calibration of a turntable for 3-D object shape reconstruction. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2001-12 |
| Volume | volume36 |
| Issue | issue1 |
| Start Page | 107 |
| End Page | 116 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 80012855284 |
| JaLCDOI | 10.18926/47003 |
|---|---|
| FullText URL | mfe_36_1_091_106.pdf |
| Author | Kanatani, Kenichi| Ohta, Naoya| |
| Abstract | We present a theoretically optimal linear algorithm for 3-D reconstruction from point correspondences over two views. We also present a similarly constructed optimal linear algorithm for 3-D reconstruction from optical flow. We then compare the performance of the two algorithms by simulation and real-image experiments using the same data. This is the first impartial comparison ever done in the sense that the two algorithms are both optimal, extracting the information contained in the data to a maximum possible degree. We observe that the finite motion solution is always superior to the optical flow solution and conclude that the finite motion algorithm should be used for 3-D reconstruction. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2001-12 |
| Volume | volume36 |
| Issue | issue1 |
| Start Page | 91 |
| End Page | 106 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120003497029 |
| JaLCDOI | 10.18926/47002 |
|---|---|
| FullText URL | mfe_36_1_079_090.pdf |
| Author | Kanatani, Kenichi| |
| Abstract | We first present an improvement of Kanatani's subspace separation [8] for motion segmentation by newly introducing the affine space constraint. We point out that this improvement does not always fare well due to the effective noise it introduces. In order to judge which solution to adopt if different segmentations are obtained, we present two criteria: one is the standard F test; the other is model selection using the geometric AIC of Kanatani [7] and the geometric MDL of Matsunaga and Kanatani [13]. We test these criteria doing real image experiments. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2001-12 |
| Volume | volume36 |
| Issue | issue1 |
| Start Page | 79 |
| End Page | 90 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120003497028 |
| JaLCDOI | 10.18926/47001 |
|---|---|
| FullText URL | mfe_36_1_059_077.pdf |
| Author | Kanatani, Kenichi| |
| Abstract | Contrasting "geometric fitting", for which the noise level is taken as the asymptotic variable, with "statistical inference", for which the number of observations is taken as the asymptotic variable, we give a new definition of the "geometric AIC" and the "geometric MDL" as the counterparts of Akaike's AIC and Rissanen's MDL. We discuss various theoretical and practical problems that emerge from our analysis. Finally, we show, doing experiments using synthetic and real images, that the geometric MDL does not necessarily outperform the geometric AIC and that the two criteria have very different characteristics. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2001-12 |
| Volume | volume36 |
| Issue | issue1 |
| Start Page | 59 |
| End Page | 77 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 80012855281 |
| JaLCDOI | 10.18926/46982 |
|---|---|
| FullText URL | mfe_37_2_073_087.pdf |
| Author | Nogami, Yasuyuki| Morikawa, Yoshitaka| |
| Abstract | Public key cryptosystem has many uses, such as to sign digitally, to realize electronic commerce. Especially, RSA public key cryptosystem has been the most widely used, but its key for ensuring sufficient security reaches about 2000 bits long. On the other hand, elliptic curve cryptosystem(ECC) has the same security level with about 7-fold smaller length key. Accordingly, ECC has been received much attention and implemented on various processors even with scarce computation resources. In this paper, we deal with an elliptic curve which is defined over extension field F(p2c) and has a prime order, where p is the characteristic and c is a non negative integer. In order to realize a fast software implementation of ECC adopting such an elliptic curve, a fast implementation method of definition field F(p2c) especially F(p8) is proposed by using a technique called successive extension. First, five fast implementation methods of base field F(p2) are introduced. In each base field implementation, calculation costs of F(p2)-arithmetic operations are evaluated by counting the numbers of F(p)-arithmetic operations. Next, a successive extension method which adopts a polynomial basis and a binomial as the modular polynomial is proposed with comparing to a conventional method. Finally, we choose two prime numbers as the characteristic, and consider several implementations for definition field F(p8) by using five base fields and two successive extension methods. Then, one of these implementations is especially selected and implemented on Toshiba 32-bit micro controller TMP94C251(20MHz) by using C language. By evaluating calculation times with comparing to previous works, we conclude that proposed method can achieve a fast implementation of ECC with a prime order. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2003-03 |
| Volume | volume37 |
| Issue | issue2 |
| Start Page | 73 |
| End Page | 87 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 80015999992 |
| JaLCDOI | 10.18926/46971 |
|---|---|
| FullText URL | mfe_37_1_041_049.pdf |
| Author | Sugaya, Yasuyuki| Kanatani, Kenichi| |
| Abstract | We study the problem of segmenting independently moving objects in a video sequence. Several algorithms exist for classifying the trajectories of the feature points into independent motions, but the performance depends on the validity of the underlying camera imaging model. In this paper, we present a scheme for automatically selecting the best model using the geometric AIC before the segmentation stage, Using real video sequences, we confirm that the segmentation accuracy indeed improves if the segmentation is based on the selected model. We also show that the trajectory data can be compressed into low-dimensional vectors using the selected model. This is very effective in reducing the computation time for a long video sequence. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2002-11 |
| Volume | volume37 |
| Issue | issue1 |
| Start Page | 41 |
| End Page | 49 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120003457326 |
| JaLCDOI | 10.18926/46970 |
|---|---|
| FullText URL | mfe_37_1_025_032.pdf |
| Author | Kanazawa, Yasushi| Kanatani, Kenichi| |
| Abstract | We present a new method for detecting point matches between two images without using any combinatorial search. Our strategy is to impose various local and non-local constraints as "soft" constraints by introducing their "confidence" measures via "mean-field approximations". The computation is a cascade of evaluating the confidence values and sorting according to them. In the end, we impose the "hard" epipolar constraint by RANSAC. We also introduce a model selection procedure to test if the image mapping can be regarded as a homography. We demonstrate the effectiveness of our method by real image examples. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2002-11 |
| Volume | volume37 |
| Issue | issue1 |
| Start Page | 25 |
| End Page | 32 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 80015664456 |
| JaLCDOI | 10.18926/46969 |
|---|---|
| FullText URL | mfe_37_1_015_023.pdf |
| Author | Kanatani, Kenichi| |
| Abstract | In order to facilitate smooth communications with researchers in other fields including statistics, this paper investigates the meaning of "statistical methods" for geometric inference based on image feature points, We point out that statistical analysis does not make sense unless the underlying "statistical ensemble" is clearly defined. We trace back the origin of feature uncertainty to image processing operations for computer vision in general and discuss the implications of asymptotic analysis for performance evaluation in reference to "geometric fitting", "geometric model selection", the "geometric AIC", and the "geometric MDL". Referring to such statistical concepts as "nuisance parameters", the "Neyman-Scott problem", and "semiparametric models", we point out that simulation experiments for performance evaluation will lose meaning without carefully considering the assumptions involved and intended applications. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2002-11 |
| Volume | volume37 |
| Issue | issue1 |
| Start Page | 15 |
| End Page | 23 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 80015664455 |
| JaLCDOI | 10.18926/46953 |
|---|---|
| FullText URL | mfe_38_1-2_061_071.pdf |
| Author | Kanatani, Kenichi| Sugaya, Yasuyuki| |
| Abstract | The Tomasi-Kanade factorization for reconstructing the 3-D shape of the feature points tracked through a video stream is widely regarded as based on factorization of a matrix by SVD (singular value decomposition). This paper points out that the core principle is the affine camera approximation to the imaging geometry and that SVD is merely one means of numerical computation. We first describe the geometric structure of the problem and then give a complete programming scheme for 3-D reconstruction. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2004-03 |
| Volume | volume38 |
| Issue | issue1-2 |
| Start Page | 61 |
| End Page | 71 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 80016889443 |
| JaLCDOI | 10.18926/46952 |
|---|---|
| FullText URL | mfe_38_1-2_039_059.pdf |
| Author | Kanatani, Kenichi| |
| Abstract | We investigate the meaning of "statistical methods" for geometric inference based on image feature points. Tracing back the origin of feature uncertainty to image processing operations, we discuss the implications of asymptotic analysis in reference to "geometric fitting" and "geometric model selection", We point out that a correspondence exists between the standard statistical analysis and the geometric inference problem. We also compare the capability of the "geometric AIC" and the "geometric MDL' in detecting degeneracy. Next, we review recent progress in geometric fitting techniques for linear constraints, describing the "FNS method", the "HEIV method", the "renormalization method", and other related techniques. Finally, we discuss the "Neyman-Scott problem" and "semiparametric models" in relation to geometric inference. We conclude that applications of statistical methods requires careful considerations about the nature of the problem in question. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2004-03 |
| Volume | volume38 |
| Issue | issue1-2 |
| Start Page | 39 |
| End Page | 59 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 80016889442 |
| Author | Yanagi, Yoshinobu| Fujita, Mariko| Hisatomi, Miki| Matsuzaki, Hidenobu| Konouchi, Hironobu| Katase, Naoki| Nagatsuka, Hitoshi| Asaumi, Jun-ichi| |
|---|---|
| Published Date | 201012 |
| Publication Title | Oral Radiology |
| Volume | volume26 |
| Issue | issue2 |
| Content Type | Journal Article |
| JaLCDOI | 10.18926/AMO/46852 |
|---|---|
| FullText URL | 65_4_265.pdf |
| Author | Kojima, Katsuhide| Kato, Katsuya| Oto, Takahiro| Mitsuhashi, Toshiharu| Shinya, Takayoshi| Sei, Tetsuro| Okumura, Yoshihiro| Sato, Shuhei| Miyoshi, Shinichiro| Kanazawa, Susumu| |
| Abstract | To determine the effectiveness of living-donor lobar lung transplantation (LDLLT), it is necessary to predict the recipient's postoperative lung function. Traditionally, Date's formula, also called the segmental ratio, has used the number of lung segments to estimate the forced vital capacity (FVC) of grafts in LDLLT. To provide a more precise estimate of graft FVC, we calculated the volumes of the lower lobe and total lung using three-dimensional computed tomography (3D-CT) and the volume ratio between them. We calculated the volume ratio in 52 donors and tested the difference between the segmental volume ratios with a one-tailed t-test. We also calculated the predicted graft FVC in 21 LDLLTs using the segmental ratio pFVC(c) and the volume ratio pFVC(v), and then found the Pearson's correlation coefficients for both pFVC(c) and pFVC(v) with the recipients' actual FVC (rFVC) measured spirometrically 6 months after surgery. Significant differences were found between the segmental ratio and the average volume ratio for both sides (right, p＝0.03;left, p＝0.0003). Both pFVC(c) and pFVC(v) correlated significantly with rFVC at 6 months after surgery (p＝0.007 and 0.006). Both the conventional and the volumetric methods provided FVC predictions that correlated significantly with measured postoperative FVC. |
| Keywords | living-donor lobar lung transplantation 3D-CT volumetry |
| Amo Type | Original Article |
| Publication Title | Acta Medica Okayama |
| Published Date | 2011-08 |
| Volume | volume65 |
| Issue | issue4 |
| Publisher | Okayama University Medical School |
| Start Page | 265 |
| End Page | 268 |
| ISSN | 0386-300X |
| NCID | AA00508441 |
| Content Type | Journal Article |
| language | English |
| Copyright Holders | CopyrightⒸ 2011 by Okayama University Medical School |
| File Version | publisher |
| Refereed | True |
| PubMed ID | 21860533 |
| Web of Science KeyUT | 000294236700007 |
| Author | Nishie, Manabu| Otsuka, Shinya| Tomoda, Jun| Fujiwara, Keishi| |
|---|---|
| Published Date | 2011-08-01 |
| Publication Title | 岡山医学会雑誌 |
| Volume | volume123 |
| Issue | issue2 |
| Content Type | Journal Article |
| Author | Matsui, Yusuke| |
|---|---|
| Published Date | 2011-03-25 |
| Publication Title | |
| Content Type | Thesis or Dissertation |
| Author | Hayase, Hitoshi| |
|---|---|
| Published Date | 2011-03-25 |
| Publication Title | |
| Content Type | Thesis or Dissertation |
| JaLCDOI | 10.18926/AMO/45272 |
|---|---|
| FullText URL | 65_2_129.pdf |
| Author | Toyota, Noriko| Ogawa, Daisuke| Ishii, Keita| Hirata, Kyoji| Wada, Jun| Shikata, Kenichi| Makino, Hirofumi| |
| Abstract | A 62-year-old woman with a history of poorly controlled type 2 diabetes mellitus was admitted to our hospital with a 3-week history of mild fever, vomiting, and anorexia. Abdominal computed tomography (CT) showed bilateral hydronephrosis and gas accumulation in the urinary bladder wall and left ureter. Laboratory tests showed leukocytosis and elevated C-reactive protein level. Urine culture showed heavy growth of Escherichia coli. The final diagnosis was emphysematous cystitis. The patient was treated with systemic antibiotics and drainage using a urethral catheter. The clinical and radiographic findings resolved rapidly, and she was discharged from the hospital on day 28. Emphysematous cystitis is a relatively rare urinary tract infection associated with gas formation, and has the potential for a serious outcome if untreated. Early detection by imaging studies such as CT is important in providing prompt treatment and favorable clinical outcome. |
| Keywords | computed tomography diabetes mellitus emphysematous cystitis |
| Amo Type | Case Report |
| Publication Title | Acta Medica Okayama |
| Published Date | 2011-04 |
| Volume | volume65 |
| Issue | issue2 |
| Publisher | Okayama University Medical School |
| Start Page | 129 |
| End Page | 133 |
| ISSN | 0386-300X |
| NCID | AA00508441 |
| Content Type | Journal Article |
| language | English |
| Copyright Holders | CopyrightⒸ 2011 by Okayama University Medical School |
| File Version | publisher |
| Refereed | True |
| PubMed ID | 21519371 |
| Web of Science KeyUT | 000289818800009 |
| JaLCDOI | 10.18926/44498 |
|---|---|
| FullText URL | mfe_045_036_045.pdf |
| Author | Kanatani, Kenichi| Niitsuma, Hirotaka| |
| Abstract | We present a new method for optimally computing the 3-D rotation from two sets of 3-D data. Unlike 2-D data, the noise in 3-D data is inherently inhomogeneous and anisotropic, reflecting the characteristics of the 3-D sensing used. To cope with this, Ohta and Kanatani introduced a technique called “renormalization”. Following them, we represent a 3-D rotation in terms of a quaternion and compute an exact maximum likelihood solution using the FNS of Chojnacki et al. As an example, we consider 3-D data obtained by stereo vision and optimally compute the 3-D rotation by analyzing the noise characteristics of stereo reconstruction. We show that the widely used method is not suitable for 3-D data. We confirm that the renormalization of Ohta and Kanatani indeed computes almost an optimal solution and that, although the difference is small, the proposed method can compute an even better solution. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2011-01 |
| Volume | volume45 |
| Start Page | 36 |
| End Page | 45 |
| ISSN | 1349-6115 |
| language | English |
| Copyright Holders | Copyright © by the authors |
| File Version | publisher |
| NAID | 80021759250 |
| JaLCDOI | 10.18926/44497 |
|---|---|
| FullText URL | mfe_045_027_036.pdf |
| Author | Kanatani, Kenichi| Sugaya, Yasuyuki| |
| Abstract | We describe in detail the algorithm of bundle adjustment for 3-D reconstruction from multiple images based on our latest research results. The main focus of this paper is on the handling of camera rotations and the efficiency of computation and memory usage when the number of variables is very large; an appropriate consideration of this is the core of the implementation of bundle adjustment. Computing the fundamental matrix from two views and reconstructing the 3-D structure from multiple views, we evaluate the performance of our algorithm and discuses technical issues of bundle adjustment implementation. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2011-01 |
| Volume | volume45 |
| Start Page | 27 |
| End Page | 35 |
| ISSN | 1349-6115 |
| language | English |
| Copyright Holders | Copyright © by the authors |
| File Version | publisher |
| NAID | 80021759249 |
