One-Shot Machine Unlearning with Mnemonic Code

Deep learning has achieved significant improvements in accuracy and has been applied to various fields. With the spread of deep learning, a new problem has also emerged; deep learning models can sometimes have undesirable information from an ethical standpoint. This problem must be resolved if deep learning is to make sensitive decisions such as hiring and prison sentencing. Machine unlearning (MU) is the research area that responds to such demands. MU aims at forgetting about undesirable training data from a trained deep learning model. A naive MU approach is to re-train the whole model with the training data from which the undesirable data has been removed. However, re-training the whole model can take a huge amount of time and consumes significant computer resources. To make MU even more practical, a simple-yet-effective MU method is required. In this paper, we propose a one-shot MU method, which does not need additional training. To design one-shot MU, we add noise to the model parameters that are sensitive to undesirable information. In our proposed method, we use the Fisher information matrix (FIM) to estimate the sensitive model parameters. Training data were usually used to evaluate the FIM in existing methods. In contrast, we avoid the need to retain the training data for calculating the FIM by using class-specific synthetic signals called mnemonic code. Extensive experiments using artificial and natural datasets demonstrate that our method outperforms the existing methods.Comment: 14 pages, welcome coment

Effect of Particle Properties on Fluidized Powder Conveying in a Horizontal Channel

AbstractThis study experimentally investigated the dense phase pneumatic conveying in a horizontal rectangular channel using the fluidizing air. The powder used the glass beads belongs to Geldart B particle, where the mean particle diameter is 127μm, the particle density is 2623kg/m3 and the minimum fluidizing velocity is 12.3mm/s. The experimental device consists of a powder discharge vessel, a horizontal rectangular channel at the side of vessel and the air supply section at the bottom of the vessel and the horizontal channel. The powder was fluidized by air through the porous membrane of the air supply section at the bottom of the vessel and the horizontal channel. Then, this system can be conveyed the fluidized powder. As the result, we confirmed the requirement that the fluidizing air to the bottom of the powder discharge vessel was required to the powder conveying of this system, and that the fluidizing velocity at the bottom of the horizontal channel was larger than that of the minimum fluidizing velocity. This result means that the fluidizing velocity at the bottom of the vessel and the horizontal channel is important to obtain the stable powder conveying. The mass flow rate and solid loading ratio were estimated by the measured data of the mass of transported powder. In addition, these results were compared with the conveying characteristic of the glass beads of 53μm belongs to Geldart A particle. Then, the mass flow rate of Geldart A particle was higher than that of Geldart B particle. The solid loading ratio of the Geldart A particle was also greatly large to that of Geldart B particle. Therefore, we considered that the high conveying efficiency to Geldart A particle was obtained, when the dimensionless fluidizing velocities at the bottom of the powder discharge vessel and the horizontal channel were same condition

Revisiting Permutation Symmetry for Merging Models between Different Datasets

Model merging is a new approach to creating a new model by combining the weights of different trained models. Previous studies report that model merging works well for models trained on a single dataset with different random seeds, while model merging between different datasets is difficult. Merging knowledge from different datasets has practical significance, but it has not been well investigated. In this paper, we investigate the properties of merging models between different datasets. Through theoretical and empirical analyses, we find that the accuracy of the merged model decreases more significantly as the datasets diverge more and that the different loss landscapes for each dataset make model merging between different datasets difficult. We also show that merged models require datasets for merging in order to achieve a high accuracy. Furthermore, we show that condensed datasets created by dataset condensation can be used as substitutes for the original datasets when merging models. We conduct experiments for model merging between different datasets. When merging between MNIST and Fashion- MNIST models, the accuracy significantly improves by 28% using the dataset and 25% using the condensed dataset compared with not using the dataset.Comment: 18 pages; comments are welcom

Caffeine-Stimulated Intestinal Epithelial Cells Suppress Lipid Accumulation in Adipocytes

Caffeine is a methylxanthine derived from plant foods such as coffee beans and tea leaves, and has multiple biological activities against physiological response and several diseases. Although there are some reports about the direct effect of caffeine against anti-lipid accumulation in vitro, the effect of caffeine on lipid accumulation in adipocytes through stimulating intestinal epithelial cells is unknown. Since direct treatment with caffeine to 3T3-L1 cells did not affect lipid accumulation, we determined whether caffeine-stimulated intestinal epithelial Caco-2 cells influence the lipid accumulation in 3T3-L1 adipocytes. Caco-2 cells were cultured on a transwell insert with or without caffeine for 24 h. Subsequently, the basolateral component of the Caco-2 cell culture on the transwell was collected and termed caffeine-conditioning medium (CCM). When 3T3-L1 adipocytes were incubated with CCM, CCM decreased lipid accumulation and suppressed gene expression of proliferator activated receptor (PPAR) γ and CCAAT/enhancer binding protein (C/EBP) α in 3T3-L1 adipocytes. Furthermore, CCM decreased the expression of C/EBPβ and C/EBPδ at the protein level, but not at the mRNA level. We observed that a proteasome inhibitor, MG132, inhibited CCM-caused down-expression of C/EBPβ and C/EBPδ proteins, and that CCM promoted the ubiquitination level of C/EBPβ and C/EBPδ proteins. Protein microarray analysis showed caffeine suppresses the secretion of inflammatory cytokines, interleukin-8 and plasminogen activator inhibitor-1 from Caco-2 cells. These results suggest that caffeine indirectly suppresses lipid accumulation in 3T3-L1 adipocytes through decreasing secretion of inflammatory cytokines from Caco-2 cells.ArticleJournal of Nutritional Science and Vitaminology. 63(5): 331-338. (2017)journal articl

Staudingerライゲーションを用いたα,β-不飽和ペプチドの合成

学位の種別: 課程博士審査委員会委員 : （主査）東京大学教授 井上 将行, 東京大学教授 大和田 智彦, 東京大学教授 金井 求, 東京大学教授 浦野 泰照, 東京大学准教授 岡田 正弘University of Tokyo(東京大学

Fixation Strength of Caudal Pedicle Screws after Posterior Lumbar Interbody Fusion with the Modified Cortical Bone Trajectory Screw Method

Study DesignClinical case series.PurposeIn the posterior lumbar interbody fusion (PLIF) procedure in our institute, the cephalad screw trajectory follows a mediolateral and caudocephalad directed path according to the original cortical bone trajectory (CBT) method. However, the starting point of the caudal screw is at the medial border of the pedicle on an articular surface of the superior articular process, and the trajectory takes a mediolateral path parallel to the cephalad endplate. The incidence of caudal screw loosening after PLIF with this modified CBT screw method was investigated, and significant risk factors for caudal screw loosening were evaluated.Overview of LiteratureA biomechanical study of this modified caudal screw trajectory using the finite element method reported about a 20% increase in uniaxial yield pullout load compared with the traditional trajectory. However, there has been no clinical study concerning the fixation strength of this modified caudal screw trajectory.MethodsThe subjects were 193 consecutive patients who underwent single-level PLIF with modified CBT screw fixation. Caudal screw loosening was checked in computed tomography at 6 months after surgery, and screw loosening was defined as a radiolucency of 1 mm or more at the bone-screw interface.ResultsThe incidence of caudal screw loosening after lumbosacral PLIF (46.2%) was significantly higher than that after floating PLIF (6.0%). No significant differences in sex, brand of the instruments, and diameter and length of the caudal screw were evident between patients with and without caudal screw loosening. Patients with caudal screw loosening were significantly older at the time of surgery than patients without caudal screw loosening.ConclusionsFixation strength of the caudal screw after floating PLIF with this modified CBT screw technique was sufficiently acceptable. Fixation strength after the lumbosacral procedure was not

Effect of Hemocoagulase on the Prevention of Bleeding after Percutaneous Renal Biopsy

A percutaneous renal biopsy is an essential tool for the diagnosis of various renal diseases;however, post-biopsy bleeding is a major complication. Hemocoagulase is a detoxified and purified snake venom enzyme that is widely used to prevent post-procedural bleeding. In this study, we retrospectively analyzed the effect of hemocoagulase on post-renal biopsy bleeding. We included 221 patients who underwent percutaneous renal biopsy between April 2017 and December 2020 and analyzed post-renal biopsy hemoglobin (Hb) decline in patients who were administered a periprocedural hemocoagulase injection. After the renal biopsy, the mean Hb decrease in the entire patient cohort was 0.33 ・ 0.84 g/dL. Periprocedural hemocoagulase injection lowered the Hb decline post-renal biopsy (0.50 ・ 0.87 vs. 0.23 ・ 0.80 g/dL, p = 0.0204). The propensity-matched cohort was also adjusted for factors influencing postprocedural bleeding; periprocedural hemocoagulase injection reduced the Hb decline post-renal biopsy (0.56 ・ 0.89 vs. 0.17 ・ 0.74 g/dL, p = 0.006). There were no adverse events (e.g., thrombosis and anaphylactic shock) due to hemocoagulase. Our study demonstrated the beneficial effect of hemocoagulase on post-renal biopsy Hb decline, suggesting its clinical value in preventing post-renal biopsy bleeding