198 research outputs found

    ANALYZING CLUSTERED LONGITUDINAL DATA USING LATENT CURVE MODEL WITH STRUCTURED RESIDUALS (LCM-SR)

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    The LCM-SR can provide an inferential basis for understanding reciprocal relations while controlling for individual differences in the trajectories of young children’s psychological development. Yet, a hierarchical structure in the data has not been often adequately addressed even though that is common in social and educational research. The purpose of this study is to explore the impact of dependency among observations on the results when using the LCM-SR, and how to appropriately analyze the clustered longitudinal data for more accurate inference. To do this, the MLCM-SR (disaggregated approach; the “two-level” model) was introduced and compared with the single level LCM-SR considering nesting effects (aggregated approach; the “complex” model), and the single level LCM-SR ignoring nesting effects (conventional approach; the “default” model). This study used both simulated data and actual data to compare the performances of the models. The simulation study results showed that all the models showed high rates of non-convergence or improper solutions in certain conditions, especially in low sample size conditions. The total number of proper solutions was higher for the complex/default model than for the two-level model in general. Also, bad model fit, severe bias, low coverage rate, and low power were found in conditions with a large percentage of variance as well as a large residual variance at the between-group level. The severity of bias increased as the sample size decreased. The two-level model showed little or no bias in general, thus showing a decent level of power and a nominal level of type 1 error rate. The actual data analysis results showed that even though there was a difference in the standard errors found between the models, using different modeling strategies did not lead to different conclusions. Advisor: James Bovair

    CAST: Cross-Attention in Space and Time for Video Action Recognition

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    Recognizing human actions in videos requires spatial and temporal understanding. Most existing action recognition models lack a balanced spatio-temporal understanding of videos. In this work, we propose a novel two-stream architecture, called Cross-Attention in Space and Time (CAST), that achieves a balanced spatio-temporal understanding of videos using only RGB input. Our proposed bottleneck cross-attention mechanism enables the spatial and temporal expert models to exchange information and make synergistic predictions, leading to improved performance. We validate the proposed method with extensive experiments on public benchmarks with different characteristics: EPIC-KITCHENS-100, Something-Something-V2, and Kinetics-400. Our method consistently shows favorable performance across these datasets, while the performance of existing methods fluctuates depending on the dataset characteristics.Comment: This is an accepted NeurIPS 2023. Project webpage is available at https://jong980812.github.io/CAST.github.io/ Code is available at https://github.com/KHU-VLL/CAS

    Cryptanalysis of and Improvement on Biometric-based User Authentication Scheme for C/S System

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    Password-based authentication schemes are convenient, but vulnerable to simple dictionary attacks. Cryptographic secret keys are safe, but difficult to memorize. More recently, biometric information has been used for authentication schemes. Das proposed a biometric-based authentication scheme, but it has various vulnerabilities. Jiping et al. improved Das’s scheme, but some vulnerabilities remain. In this paper, we analyze the cryptanalysis of Jiping et al.’s authentication scheme and propose the security enhanced biometric-based user authentication scheme for the C/S System

    Cryptanalysis and Improvement on Robust Three-Factor Remote User Authentication Scheme with Key Agreement for Multimedia System

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    A three-factor authentication combines biometrics information with user password and smart card to provide security-enhanced user authentication. An proposed user authentication scheme improved Das’s scheme. But An’s scheme is not secure against denial of service attack in login phase, forgery attack. Li et al. pointed out them and proposed three-factor remote user authentication scheme with key agreement. However, Li et al’s scheme still has some security problem. In this paper, we present a cryptanalysis and improvement of Li et al.’s remote user authentication scheme

    Society Key: Integrating Social Media Data with Governmental Open Data to Encourage Community Wellbeing

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    In this paper, we present a service incorporating an electronic online system that integrates data from multiple social media sources and multiple governmental open data sources with the intention of improving awareness of available societal data and to encourage individuals and groups of people to take action towards the wellbeing of their local communities. We call our proposed service/system, “Society Key”.ye

    Clinical implications of advances in liver regeneration

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    Remarkable advances have been made recently in the area of liver regeneration. Even though liver regeneration after liver resection has been widely researched, new clinical applications have provided a better understanding of the process. Hepatic damage induces a process of regeneration that rarely occurs in normal undamaged liver. Many studies have concentrated on the mechanism of hepatocyte regeneration following liver damage. High mortality is usual in patients with terminal liver failure. Patients die when the regenerative process is unable to balance loss due to liver damage. During disease progression, cellular adaptations take place and the organ microenvironment changes. Portal vein embolization and the associating liver partition and portal vein ligation for staged hepatectomy are relatively recent techniques exploiting the remarkable progress in understanding liver regeneration. Living donor liver transplantation is one of the most significant clinical outcomes of research on liver regeneration. Another major clinical field involving liver regeneration is cell therapy using adult stem cells. The aim of this article is to provide an outline of the clinical approaches being undertaken to examine regeneration in liver diseases

    Vehicle Trajectory Prediction and Collision Warning via Fusion of Multisensors and Wireless Vehicular Communications

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    Driver inattention is one of the leading causes of traffic crashes worldwide. Providing the driver with an early warning prior to a potential collision can significantly reduce the fatalities and level of injuries associated with vehicle collisions. In order to monitor the vehicle surroundings and predict collisions, on-board sensors such as radar, lidar, and cameras are often used. However, the driving environment perception based on these sensors can be adversely affected by a number of factors such as weather and solar irradiance. In addition, potential dangers cannot be detected if the target is located outside the limited field-of-view of the sensors, or if the line of sight to the target is occluded. In this paper, we propose an approach for designing a vehicle collision warning system based on fusion of multisensors and wireless vehicular communications. A high-level fusion of radar, lidar, camera, and wireless vehicular communication data was performed to predict the trajectories of remote targets and generate an appropriate warning to the driver prior to a possible collision. We implemented and evaluated the proposed vehicle collision system in virtual driving environments, which consisted of a vehicle&ndash vehicle collision scenario and a vehicle&ndash pedestrian collision scenario. Document type: Articl

    Association between diet and gallstones of cholesterol and pigment among patients with cholecystectomy: a case-control study in Korea

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    Background: The prevalence of cholesterol gallstones is high in Western populations, while pigment gallstones are common in Asian populations. Dietary factors are suggested to be associated with gallstone risk, but their relationship with gallstone type has not been evaluated. This study investigated the association between diet and risk of cholesterol gallstone or pigment gallstone in a Korean population whose dietary pattern and type of gallstone were changed during the last 30 years. Methods: Patients with cholesterol (n = 40) and pigment (n = 59) gallstones were recruited after laparoscopic cholecystectomy and were compared with those of age- and sex-matched controls without gallstones (n = 99). Dietary intakes were assessed by trained dietitians using a semi-quantitative food frequency questionnaire. Multinomial logistic regression analysis was performed to calculate odds ratios and 95% confidence intervals to examine the associations between diet and risk for type of gallstones adjusted by potential confounders. Results: Patients with cholesterol gallstone consumed more lipid, animal lipid, beef, pork, and fried food than those with pigment gallstones and control, while patients with pigment gallstone consumed more carbohydrate and noodles than patients with cholesterol gallstone and control. In multinomial logistic regression analysis using control as reference group, dietary pattern with high consumption of beef, pork, and fried food was associated with risk of cholesterol gallstones, while there was no association between the risk of pigment gallstone and dietary pattern. In addition, control consumed more alcohol than patients with cholesterol and pigment gallstones. Conclusions: The present study suggested consumption of fat from meat and fried foods increased the risk of cholesterol gallstone, and intake of carbohydrate from noodles increased the risk of pigment gallstone

    Efficient Ruddlesden-Popper Perovskite Light-Emitting Diodes with Randomly Oriented Nanocrystals

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    Ruddlesden-Popper phase (RP-phase) perovskites that consist of 2D perovskite slabs interleaved with bulky organic ammonium (OA) are favorable for light-emitting diodes (LEDs). The critical limitation of LED applications is that the insulating OA arranged in a preferred orientation limits charge transport. Therefore, the ideal solution is to achieve a randomly connected structure that can improve charge transport without hampering the confinement of the electron-hole pair. Here, a structurally modulated RP-phase metal halide perovskite (MHP), (PEA)(2)(CH3NH3)(m-1)PbmBr3m+1 is introduced to make the randomly oriented RP-phase unit and ensure good connection between them by applying modified nanocrystal pinning, which leads to an increase in the efficiency of perovskite LEDs (PeLEDs). The randomly connected RP-phase MHP forces contact between inorganic layers and thereby yields efficient charge transport and radiative recombination. Combined with an optimal dimensionality, (PEA)(2)(CH3NH3)(2)Pb3Br10, the structurally modulated RP-phase MHP exhibits increased photoluminescence quantum efficiency, from 0.35% to 30.3%, and their PeLEDs show a 2,018 times higher current efficiency (20.18 cd A(-1)) than in the 2D PeLED (0.01 cd A(-1)) and 673 times than in the 3D PeLED (0.03 cd A(-1)) using the same film formation process. This approach provides insight on how to solve the limitation of RP-phase MHP for efficient PeLEDs.
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