Convergence analysis of recurrent neural network with self-loops based on eigenvalues of a connection matrix

金沢大学理工研究域電子情報学系Recurrent Neural Network (RNN) can be applied to solve a combinatorial optimization problem. However, the existence of the local minima in this model prevents its application to real world. In this paper, an analysis method for network dynamics based on eigenvalues and eigenvectors of a connection weight matrix is proposed. In this analysis, the transition of the number of negative eigenvalues and the movement of eigenspaces by increasing diagonal elements, which correspond to feedback loops of RNN, are discussed. From this analysis, it is confirmed that the number of negative eigenvalues decreases and the eigenspaces move toward the ascent side of the energy slope at the center point of the state space of RNN, as increasing diagonal elements. These behaviors of RNN contribute to the improvement for searching a solution of a combinatorial optimization problem. This analysis method is applied to a 2-dimensional example and 5 cities T.S. problems. From this analysis, it is theoretically found that the network performance of detecting the optimal solution can be improved by increasing the values of diagonal elements of connection matrix

Comparison of gravity wave propagation directions observed by mesospheric airglow imaging at three different latitudes using the M-transform

We developed user-friendly software based on Matsuda et al.'s (2014) 3D-FFT method (Matsuda-transform, M-transform) for airglow imaging data analysis as a function of Interactive Data Language (IDL). Users can customize the range of wave parameters to process when executing the program. The input for this function is a 3-D array of a time series of a 2-D airglow image in geographical coordinates. We applied this new function to mesospheric airglow imaging data with slightly different observation parameters obtained for the period of April–May at three different latitudes: Syowa Station, the Antarctic (69∘&thinsp;S, 40∘&thinsp;E); Shigaraki, Japan (35∘&thinsp;N, 136∘&thinsp;E); and Tomohon, Indonesia (1∘&thinsp;N, 122∘&thinsp;E). The day-to-day variation of the phase velocity spectrum at the Syowa Station is smaller and the propagation direction is mainly westward. In Shigaraki, the day-to-day variation of the horizontal propagation direction is larger than that at the Syowa Station; the variation in Tomohon is even larger. In Tomohon, the variation of the nightly power spectrum magnitude is remarkable, which indicates the intermittency of atmospheric gravity waves (AGWs). The average nightly spectrum obtained from April–May shows that the dominant propagation is westward with a phase speed &lt;50&thinsp;m&thinsp;s−1 at the Syowa Station and east-southeastward with a phase speed of up to ∼80&thinsp;m&thinsp;s−1 in Shigaraki. The day-to-day variation in Tomohon is too strong to discuss average characteristics; however, a phase speed of up to ∼100&thinsp;m&thinsp;s−1 and faster is observed. The corresponding background wind profiles derived from MERRA-2 indicate that wind filtering plays a significant role in filtering out waves that propagate eastward at the Syowa Station. On the other hand, the background wind is not strong enough to filter out relatively high-speed AGWs in Shigaraki and Tomohon and the dominant propagation direction is likely related to the distribution and characteristics of the source region, at least in April and May.</p

Extended Hemi-Hepatectomy with Portal Vein Reconstruction in a Patient with Situs Ambiguous

We report a case of far-advanced hepatocellular carcinoma (HCC) with situs ambiguous, complex visceral and vascular anomalies, who was successfully managed by extended hemi-hepatectomy. A 67-year-old man was referred to our hospital with a large liver mass. Abdominal ultrasonography, computed tomography and angiography revealed HCC with a diameter of 10 cm, with tumor thrombus in the main and first branch of the portal vein. Multiple complex anomalies in the abdomen were determined preoperatively. He had right-sided spleens-stomach-duodenum, liver at midline, inferior vena cava interruption with azygous continuation, and hepatic arterial anomaly. Extended left lobectomy of the liver with reconstruction of the portal vein was performed. Postoperatively, the patient recovered without major complications, and he was discharged on postoperative day 21. We report the first successful extended hepatectomy with portal vein reconstruction for HCC in a patient with rare situs anomalies

Successful Treatment for Hepatic Encephalopathy Aggravated by Portal Vein Thrombosis with Balloon-Occluded Retrograde Transvenous Obliteration

This report presents the case of a 78-year-old female with hepatic encephalopathy due to an inferior mesenteric venous-inferior vena cava shunt. She developed hepatocellular carcinoma affected by hepatitis C virus-related cirrhosis and underwent posterior sectionectomy. Portal vein thrombosis developed and the portal trunk was narrowed after hepatectomy. Portal vein thrombosis resulted in high portal pressure and increased blood flow in an inferior mesenteric venous-inferior vena cava shunt, and hepatic encephalopathy with hyperammonemia was aggravated. The hepatic encephalopathy aggravated by portal vein thrombosis was successfully treated by balloon-occluded retrograde transvenous obliteration via a right transjugular venous approach without the development of other collateral vessels

Tratamento da lombalgia crônica pela inativação de pontosgatilho miofasciais: experiência da Divisão de Medicina Física da FMUSP

Low back pain is one of the most frequent cause of disability. This study presents the protocol and evaluation of the therapeutic effects using trigger point injections to treat chronic low back pain on a group of 25 pacients, 8 males and 17 females that did not respond to conventional approach. The results showed statistically significant improvement in pain intensity and dolorimetry. The authors concluded that trigger point injection is a efficient therapeutic method of chronic low back pain treatment when others fail.A lombalgia é uma das causas freqüentes de incapacidade. Este estudo apresenta protocolo e avaliação dos resultados dos efeitos terapêuticos, utilizando-se a técnica de injeção do ponto-gatilho de Fischer no tratamento da dor lombar crônica em um grupo de 25 pacientes, 8 homens e 17 mulheres, que não responderam à abordagem convencional. Os resultados mostraram melhora estatisticamente significante na intensidade da dor e algometria. Os autores concluíram que a inativação dos pontosgatilho é uma modalidade terapêutica eficiente no tratamento da lombalgia crônica quando outras falham

Characteristics of mesospheric gravity waves over Antarctica observed by Antarctic Gravity Wave Instrument Network imagers using 3-D spectral analyses

We have obtained horizontal phase velocity distributions of the gravity waves around 90 km from four Antarctic airglow imagers, which belong to an international airglow imager/instrument network known as ANGWIN (Antarctic Gravity Wave Instrument Network). Results from the airglow imagers at Syowa (69°S, 40°E), Halley (76°S, 27°W), Davis (69°S, 78°E) and McMurdo (78°S, 167°E) were compared, using a new statistical analysis method based on 3-D Fourier transform [Matsuda et al., 2014] for the observation period between 7 April and 21 May 2013. Significant day-to-day and site-to-site differences were found. The averaged phase velocity spectrum during the observation period showed preferential westward direction at Syowa, McMurdo and Halley, but no preferential direction at Davis. Gravity wave energy estimated by I’/I was ~5 times larger at Davis and Syowa than at McMurdo and Halley. We also compared the phase velocity spectrum at Syowa and Davis with the background wind field and found that the directionality only over Syowa could be explained by critical level filtering of the waves. This suggests that the eastward propagating gravity waves over Davis could have been generated above the polar night jet. Comparison of nighttime variations of the phase velocity spectra with background wind measurements suggested that the effect of critical level filtering could not explain the temporal variation of gravity wave directionality well, and other reasons such as variation of wave sources should be taken into account. Directionality was determined to be dependent on the gravity wave periods

Seasonal variation of temperature and gravity wave activities in the upper stratosphere - lower mesosphere observed by Rayleigh lidar at Syowa in 2011-2012

第3回極域科学シンポジウム　横断セッション「中層大気・熱圏」 11月26日（月）、27日（火） 国立極地研究所 ２階ラウン