Inexact Online Proximal Mirror Descent for time-varying composite optimization

In this paper, we consider the online proximal mirror descent for solving the time-varying composite optimization problems. For various applications, the algorithm naturally involves the errors in the gradient and proximal operator. We obtain sharp estimates on the dynamic regret of the algorithm when the regular part of the cost is convex and smooth. If the Bregman distance is given by the Euclidean distance, our result also improves the previous work in two ways: (i) We establish a sharper regret bound compared to the previous work in the sense that our estimate does not involve $O(T)$ term appearing in that work. (ii) We also obtain the result when the domain is the whole space $\mathbb{R}^n$, whereas the previous work was obtained only for bounded domains. We also provide numerical tests for problems involving the errors in the gradient and proximal operator.Comment: 16 pages, 5 figure

High-efficiency Bidirectional Buck-Boost Converter for Residential Energy Storage System

This paper proposes a bidirectional dc-dc converter for residential micro-grid applications. The proposed converter can operate over an input voltage range that overlaps the output voltage range. This converter uses two snubber capacitors to reduce the switch turn-off losses, a dc-blocking capacitor to reduce the input/output filter size, and a 1:1 transformer to reduce core loss. The windings of the transformer are connected in parallel and in reverse-coupled configuration to suppress magnetic flux swing in the core. Zero-voltage turn-on of the switch is achieved by operating the converter in discontinuous conduction mode. The experimental converter was designed to operate at a switching frequency of 40-210 kHz, an input voltage of 48 V, an output voltage of 36-60 V, and an output power of 50-500 W. The power conversion efficiency for boost conversion to 60 V was >= 98.3% in the entire power range. The efficiency for buck conversion to 36 V was >= 98.4% in the entire power range. The output voltage ripple at full load was <3.59 V-p.p for boost conversion (60 V) and 1.35 V-p.p for buck conversion (36 V) with the reduced input/output filter. The experimental results indicate that the proposed converter is well-suited to smart-grid energy storage systems that require high efficiency, small size, and overlapping input and output voltage ranges.11Ysciescopu

Improvement of Mechanical Properties of UV-curable Resin for High-aspect Ratio Microstructures Fabricated in Microstereolithography

Recently, microstructures fabricated using microstereolithography technology have been used in the biological, medical and mechanical fields. Microstereolithography can fabricate real 3D microstructures with fine features, although there is presently a limited number of materials available for use in the process. Deformation of the fine features on a fabricated microstructure remains a critical issue for successful part fabrication, and part deformation can occur during rinsing or during fabrication as a result of fluid flow forces that occur during movement of mechanical parts of the system. Deformation can result in failure to fabricate a particular feature by breaking the feature completely, spatial deflection of the feature, or attaching the feature to neighboring microstructures. To improve mechanical strength of fabricated microstructures, a clay nanocomposite can be used. In particular, a high-aspect ratio microstructure can be fabricated without distortion using photocurable liquid resin containing a clay nanocomposite. In this paper, a clay nanocomposite was blended with a photocurable liquid resin to solve the deformation problem that occurs during fabrication and rinsing. An optimal mixture ratio of a clay nanocomposite was found through tensile testing and the minimal allowable distance between microstructures was found through fabrication experimentation. Finally, using these results, high-aspect ratio microstructures were fabricated using a clay nanocomposite resin without distortion

Resting-state EEG activity related to impulsivity in gambling disorder

Background and aims Impulsivity is a core feature of gambling disorder (GD) and is related to the treatment response. Thus, it is of interest to determine objective neurobiological markers associated with impulsivity in GD. We explored resting-state electroencephalographic (EEG) activity in patients with GD according to the degree of impulsivity. Methods In total, 109 GD subjects were divided into three groups according to Barratt impulsiveness scale-11 (BIS-11) scores: high (HI; 25th percentile of BIS-11 scores, n = 29), middle (MI; 26th–74th percentile, n = 57), and low-impulsivity (LI) groups (75th percentile, n = 23). We used generalized estimating equations to analyze differences in EEG absolute power considering group (HI, MI, and LI), brain region (frontal, central, and posterior), and hemisphere (left, midline, and right) for each frequency band (delta, theta, alpha, beta, and gamma). Results The results indicated that GD patients in the HI group showed decreased theta absolute power, and decreased alpha and beta absolute power in the left, right, particularly midline frontocentral regions. Discussion and conclusions This study is a novel attempt to reveal impulsive features in GD by neurophysiological methods. The results suggest different EEG patterns among GD patients according to the degree of impulsivity, raising the possibility of neurophysiological objective features in GD and helping clinicians in treating GD patients with impulsive features

Similarities and differences among Internet gaming disorder, gambling disorder and alcohol use disorder: A focus on impulsivity and compulsivity

Background and aims: The aim of the present study was to test the impulsivities and compulsivities of behavioral addictions, including Internet gaming disorder (IGD) and gambling disorder (GD), by directly comparing them with alcohol use disorder (AUD) and a healthy control (HC) group. Methods: We enrolled male patients who were diagnosed with IGD, GD or AUD, with 15 patients per group, as well as 15 HCs. Trait impulsivity was measured using the Barratt Impulsiveness Scale version 11 (BIS-11). The stop-signal test (SST) from the Cambridge Neuro-psychological Test Automated Battery (CANTAB) was used to assess the patients’ abilities to inhibit prepotent responses. Compulsivity was measured using the intra–extra dimensional set shift (IED) test from the CANTAB. The Trail Making Test (TMT) was also used in this study. Results: The IGD and AUD groups scored significantly higher on the BIS-11 as a whole than did the HC group (p = 0.001 and p = 0.001, respectively). The IGD and AUD groups also scored significantly higher on the BIS-11 as a whole than did the GD group (p = 0.006 and p = 0.001, respectively). In addition, the GD group made significantly more errors (p = 0.017 and p = 0.022, respectively) and more individuals failed to achieve criterion on the IED test compared with the IGD and HC groups (p = 0.018 and p = 0.017, respectively). Discussion: These findings may aid in the understanding of not only the differences in categorical aspects between individuals with IGD and GD but also in impulsivity–compulsivity dimensional domains. Conclusion: Additional studies are needed to elucidate the neurocognitive characteristics of behavioral addictive disorders in terms of impulsivity and compulsivity

Predictors of intentional intoxication using decision tree modeling analysis: a retrospective study

Objective The suicide rate in South Korea is very high and is expected to increase in coming years. Intoxication is the most common suicide attempt method as well as one of the common reason for presenting to an emergency medical center. We used decision tree modeling analysis to identify predictors of risk for suicide by intentional intoxication. Methods A single-center, retrospective study was conducted at our hospital using a 4-year registry of the institute from January 1, 2013 to December 31, 2016. Demographic factors, such as sex, age, intentionality, therapeutic adherence, alcohol consumption, smoking status, physical disease, cancer, psychiatric disease, and toxicological factors, such as type of intoxicant and poisoning severity score were collected. Candidate risk factors based on the decision tree were used to select variables for multiple logistic regression analysis. Results In total, 4,023 patients with intoxication were enrolled as study participants, with 2,247 (55.9%) identified as cases of intentional intoxication. Reported annual percentages of intentional intoxication among patients were 628/937 (67.0%), 608/1,082 (56.2%), 536/1,017 (52.7), 475/987 (48.1%) from 2013 to 2016. Significant predictors identified based on decision tree analysis were alcohol consumption, old age, psychiatric disease, smoking, and male sex; those identified based on multiple regression analysis were alcohol consumption, smoking, male sex, psychiatric disease, old age, poor therapeutic adherence, and physical disease. Conclusion We identified important predictors of suicide risk by intentional intoxication. A specific and realistic approach to analysis using the decision tree modeling technique is an effective method to determine those groups at risk of suicide by intentional intoxication

Effects of PI3Kγ overexpression in the hippocampus on synaptic plasticity and spatial learning

Previous studies have shown that a family of phosphoinositide 3-kinases (PI3Ks) plays pivotal roles in the brain; in particular, we previously reported that knockout of the γ isoform of PI3K (PI3Kγ) in mice impaired synaptic plasticity and reduced behavioral flexibility. To further examine the role of PI3Kγ in synaptic plasticity and hippocampus-dependent behavioral tasks we overexpressed p110γ, the catalytic subunit of PI3Kγ, in the hippocampal CA1 region. We found that the overexpression of p110γ impairs NMDA receptor-dependent long-term depression (LTD) and hippocampus-dependent spatial learning in the Morris water maze (MWM) task. In contrast, long-term potentiation (LTP) and contextual fear memory were not affected by p110γ overexpression. These results, together with the previous knockout study, suggest that a critical level of PI3Kγ in the hippocampus is required for successful induction of LTD and normal learning

Air pollution and hemorrhagic fever with renal syndrome in South Korea: an ecological correlation study

Background : The effects of air pollution on the respiratory and cardiovascular systems, and the resulting impacts on public health, have been widely studied. However, little is known about the effect of air pollution on the occurrence of hemorrhagic fever with renal syndrome (HFRS), a rodent-borne infectious disease. In this study, we evaluated the correlation between air pollution and HFRS incidence from 2001 to 2010, and estimated the significance of the correlation under the effect of climate variables. Methods : We obtained data regarding HFRS, particulate matter smaller than 10 μm (PM10) as an index of air pollution, and climate variables including temperature, humidity, and precipitation from the national database of South Korea. Poisson regression models were established to predict the number of HFRS cases using air pollution and climate variables with different time lags. We then compared the ability of the climate model and the combined climate and air pollution model to predict the occurrence of HFRS. Results : The correlations between PM10 and HFRS were significant in univariate analyses, although the direction of the correlations changed according to the time lags. In multivariate analyses of adjusted climate variables, the effects of PM10 with time lags were different. However, PM10 without time lags was selected in the final model for predicting HFRS cases. The model that combined climate and PM10 data was a better predictor of HFRS cases than the model that used only climate data, for both the study period and the year 2011. Conclusions : This is the first report to document an association between HFRS and PM10 level.This work was supported by a grant from the Korean Healthcare Technology R&D Project, Ministry for Health, Welfare & Family Affairs, Republic of Korea (A084001).Peer Reviewe