Computing User Reputation in a Social Network of Web 2.0

In the Web 2.0 era, people not only read web contents but create, upload, view, share and evaluate all contents on the web. This leads us to introduce a new type of social network based on user activity and content metadata. We notice that we can determine the quality of related contents using this new social network. Based on this observation, we introduce a user evaluation algorithm for user-generated video sharing website. First, we make a social network of users from video contents and related social activities such as subscription, uploading or favorite. We then use a modified PageRank algorithm to compute user reputation from the social network. We re-calculate the content scores using user reputations and compare the results with a standard BM25 result. We apply the proposed approach to YouTube and demonstrate that the user reputation is closely related to the number of subscriptions and the number of uploaded contents. Furthermore, we show that the new ranking results relied on the user reputation is better than the standard BM25 approach by experiments

Do Bugs Propagate? An Empirical Analysis of Temporal Correlations Among Software Bugs

The occurrences of bugs are not isolated events, rather they may interact, affect each other, and trigger other latent bugs. Identifying and understanding bug correlations could help developers localize bug origins, predict potential bugs, and design better architectures of software artifacts to prevent bug affection. Many studies in the defect prediction and fault localization literature implied the dependence and interactions between multiple bugs, but few of them explicitly investigate the correlations of bugs across time steps and how bugs affect each other. In this paper, we perform social network analysis on the temporal correlations between bugs across time steps on software artifact ties, i.e., software graphs. Adopted from the correlation analysis methodology in social networks, we construct software graphs of three artifact ties such as function calls and type hierarchy and then perform longitudinal logistic regressions of time-lag bug correlations on these graphs. Our experiments on four open-source projects suggest that bugs can propagate as observed on certain artifact tie graphs. Based on our findings, we propose a hybrid artifact tie graph, a synthesis of a few well-known software graphs, that exhibits a higher degree of bug propagation. Our findings shed light on research for better bug prediction and localization models and help developers to perform maintenance actions to prevent consequential bugs

Prognostic Value of Electrophysiological Parameters for the Recovery of Motor Functions in Stroke Patients

We estimated correlations between baseline electrophysiological parameters and motor functions in patients with subacute stroke, in order to identify their predictive value for motor and functional recovery after a 4-week-long rehabilitation period. Sixty patients with subacute stroke were enrolled. Somatosensory evoked potentials (SSEPs), compound motor action potentials (CMAPs), and sensory nerve action potentials (SNAPs) were recorded, and the amplitude ratios were calculated in the components of these potentials. Clinical parameters consisted of the Korean-modified Barthel index (K-MBI), motricity index (MI), and manual function test (MFT). After the rehabilitation period, these indices were re-evaluated. The ulnar CMAP amplitude was found to significantly correlate with all clinical outcome indices. Additionally, a multivariate linear regression analysis revealed that the ulnar CAMP amplitude ratio was an independent predictor for the baseline MI of the upper extremity and K-MBI. The median SSEP amplitude ratio was an independent prognostic factor for the follow-up MI of the upper extremity, MFT, and follow-up K-MBI. Our results indicate that not only is the median SSEP amplitude ratio a prognostic factor for the motor functions and functional recovery, but also the ulnar CMAP amplitude might be an independent predictor in subacute stroke patients.Ми оцінювали кореляції між вихідними електрофізіологічними параметрами та моторними функціями у пацієнтів із підгострим інсультом з ціллю ідентифікувати прогностичну цінність цих даних для моторного та функціонального відновлення після чотиритижневого періоду реабілітації. Відводили соматосенсорні викликані потенціали (SSEP), складні моторні потенціали дії (CMAP) та складні сенсорні нервові потенціали дії (SNAP); розраховували відношення амплітуд цих потенціалів та їх компонентів. Серед клінічних параметрів оцінювали індекс Бартела, модифікований для умов Кореї (K-MBI), індекс моторної сфери (MI) та тест мануальних функцій (MFT). Ці індекси повторно оцінювалися після періоду реабілітації. Амплітуда CMAP, викликаних стимуляцією ульнарного нерва, вірогідно корелювала з усіма клінічними показниками. Крім того, аналіз мультиваріативної лінійної регресії показав, що відношення амплітуд ульнарних CAMP є незалежним предиктором вихідного MI для верхньої кінцівки та K-MBI. Відношення амплітуд SSEP, викликаних стимуляцією медіанного нерва, було незалежним прогностичним фактором для післяреабілітаційного MI верхніх кінцівок, MFT і післяреабілітаційного K-MBI. Наші результати свідчать про те, що не тільки відношення амплітуд медіанних SSEP є прогностичним фактором щодо моторних функцій та функціонального відновлення; амплітуда ульнарних CMAP теж може бути незалежним предиктором у пацієнтів із підгострим інсультом

Readout-segmented echo-planar imaging in diffusion-weighted mr imaging in breast cancer: comparison with single-shot echo-planar imaging in image quality

Objective: The purpose of this study was to compare the image quality of standard single-shot echo-planar imaging (ss-EPI) and that of readout-segmented EPI (rs-EPI) in patients with breast cancer. Materials and Methods: Seventy-one patients with 74 breast cancers underwent both ss-EPI and rs-EPI. For qualitative comparison of image quality, three readers independently assessed the two sets of diffusion-weighted (DW) images. To evaluate geometric distortion, a comparison was made between lesion lengths derived from contrast enhanced MR (CE-MR) images and those obtained from the corresponding DW images. For assessment of image parameters, signal-to-noise ratio (SNR), lesion contrast, and contrast-to-noise ratio (CNR) were calculated. Results: The rs-EPI was superior to ss-EPI in most criteria regarding the qualitative image quality. Anatomical structure distinction, delineation of the lesion, ghosting artifact, and overall image quality were significantly better in rs-EPI. Regarding the geometric distortion, lesion length on ss-EPI was significantly different from that of CE-MR, whereas there were no significant differences between CE-MR and rs-EPI. The rs-EPI was superior to ss-EPI in SNR and CNR. Conclusion: Readout-segmented EPI is superior to ss-EPI in the aspect of image quality in DW MR imaging of the breast

Determination of Thyroid Volume by Ultrasonography among Schoolchildren in Philippines

Objective. Iodine deficiency is defined by the goiter and the urinary iodine concentration. However, a lack of local thyroid volume reference data resulted in the vague definition of goiter, especially in school-aged children. The aim of this paper was to determine the thyroid volumes by ultrasonography in schoolchildren aged 6 to 12 years living in Cagayan areas in Philippine. Methods. Cross-sectional thyroid ultrasonographic data of 158 schoolchildren aged 6–12 years from Tuguegarao and Lagum in Cagayan valley, Philippine were used. Thyroid volumes were compared based on logistic issue and urban and rural area and compared with other previously reported data. Results. The mean values of thyroid volume in Tuguerago and Lagum were 2.99 ± 1.34 mL and 2.42 ± 0.92 mL. The thyroid size was significantly in association with age (P < 0.00), weight (P < 0.00), height (P < 0.00), and BSA (P < 0.00) by Pearson's correlation. The median thyroid volumes of schoolchildren investigated in this study were generally low compared to international reference data by age group but not by BSA. Conclusions. We propose for the first time local reference ultrasound values for thyroid volumes in 6–12 aged schoolchildren that should be used for monitoring iodine deficiency disorders

Stability and activity controls of Cu nanoparticles for high-performance solid oxide fuel cells

Cu-based electrodes could advance solid oxide fuel cells (SOFC) technology due to good electric conductivity and relatively high electrochemical activity among transition metals. However, one of the main challenges for designing anode materials is thermal stability in SOFC operation condition. Herein, a promising anode material decorated with Cu nanoparticles (NPs) was synthesized via in-situ exsolution from La0.43Sr0.37Cu0.12Ti0.88O3-δ (LSCuT) perovskite. Compared to infiltration process, Cu NPs prepared by in-situ exsolution displayed homogeneous nano size distribution on the substrate and excellent thermal stability at 600 °C in H2 atmosphere, for ∼50 h. In addition, we employed electrochemical reduction (ER) at 2.3 V for a few seconds to demonstrate that NPs can be rapidly grown, and the substrate reduced. A single cell with LSCuT anode (10 μm)||ScSZ electrolyte (90 μm) ||LSM-ScSZ cathode (20 μm) exhibits maximum power density of 1.38 Wcm−2 at 900 °C under wet H2. The present study provides possibility of a broad application of thermally stable Cu-based electrodes

Capacitance of MnO2 Micro-Flowers Decorated CNFs in Alkaline Electrolyte and Its Bi-Functional Electrocatalytic Activity toward Hydrazine Oxidation

Well-dispersed MnO2 micro-flowers were grown directly on carbon nanofibers via a simple hydrothermal technique without any template. Structure and morphology were characterized by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM) equipped with rapid energy dispersive analysis X-ray (EDX). The appealed characterization techniques specified that the obtained material is carbon nanofibers decorated by MnO2 micro-flowers. Super capacitive performance of the MnO2 micro-flowers decorated CNFs as active electrode material was evaluated by cyclic voltammetry (CV) in alkaline medium and yield a reasonable specific capacitance of 120 Fg−1 at 5 mV s−1. As an electrocatalyst for hydrazine oxidation, the MnO2 micro-flowers decorated CNFs showed high current density. The impressive bi-functional electrochemical activity of MnO2 micro-flowers decorated CNFs is mainly attributed to its unique architectural structure.This Research was financially supported by National Research Foundation of Korea (NRF) Grant funded by the Korean Government (MSIP) (No. 2014R1A4A1008140

Shape-shifting nanoparticles on a perovskite oxide for highly stable and active heterogeneous catalysis

Controlling the geometric shape of nano-catalysts plays a key role in maximizing unique properties of the materials. Although shape control of nanoparticles is well known by various preparation methods, still there is no clear case for exsolution. Here we show that the shape of embedded Ni nanoparticles can be changed on exsolution process, by controlling reduction temperature and time. To elucidate and generalize the shape-shifting, we develop a model which describes the equilibrium shape of nanoparticles on support thermodynamically. Our results suggest that there is a thermodynamic driving force for the exsolved nanoparticle to be stabilized into faceted shape with low surface/interface energy, during the particle growth. Through catalytic activity testing, the improved durability of shape-shifted Ni catalysts is confirmed on dry-reforming condition over 390 h, resulting from enhanced interface stability and cocking resistance. This provides theoretical and experimental framework for the shape control of exsolved particle on oxide support, but also for the design of unique catalyst with high stability and reactivity