G-Computation to Causal Mediation Analysis With Sequential Multiple Mediators—Investigating the Vulnerable Time Window of HBV Activity for the Mechanism of HCV Induced Hepatocellular Carcinoma

Regression-based approaches are widely used in causal mediation analysis. The presence of multiple mediators, however, increases the complexity and difficulty of mediation analysis. In such cases, regression-based approaches cannot efficiently address estimation issues. Hence, a flexible approach to mediation analysis is needed. Therefore, we developed a method for using g-computation algorithm to conduct causal mediation analysis in the presence of multiple ordered mediators. Compared to regression-based approaches, the proposed simulation-based approach increases flexibility in the choice of models and increases the range of the outcome scale. The Taiwanese Cohort Study dataset was used to evaluate the efficacy of the proposed approach for investigating the mediating role of early and late HBV viral load in the effect of HCV infection on hepatocellular carcinoma (HCC) in HBV seropositive patients (n = 2,878; HCV carrier n = 123). Our results indicated that early HBV viral load had a negative mediating role in HCV-induced HCC. Additionally, early exposure to a low HBV viral load affected HCC through a lag effect on HCC incidence [OR = 0.873, 95% CI = (0.853, 0.893)], and the effect of early exposure to a low HBV viral load on HCC incidence was slightly larger than that of a persistently low viral load on HCC incidence [OR = 0.918, 95% CI = (0.896, 0.941)].

Quantum algorithms for escaping from saddle points

We initiate the study of quantum algorithms for escaping from saddle points with provable guarantee. Given a function f:Rn→R, our quantum algorithm outputs an ϵ-approximate second-order stationary point using O~(log2⁡(n)/ϵ1.75) queries to the quantum evaluation oracle (i.e., the zeroth-order oracle). Compared to the classical state-of-the-art algorithm by Jin et al. with O~(log6⁡(n)/ϵ1.75) queries to the gradient oracle (i.e., the first-order oracle), our quantum algorithm is polynomially better in terms of log⁡n and matches its complexity in terms of 1/ϵ. Technically, our main contribution is the idea of replacing the classical perturbations in gradient descent methods by simulating quantum wave equations, which constitutes the improvement in the quantum query complexity with log⁡n factors for escaping from saddle points. We also show how to use a quantum gradient computation algorithm due to Jordan to replace the classical gradient queries by quantum evaluation queries with the same complexity. Finally, we also perform numerical experiments that support our theoretical findings.

Test and Theory for a Refined Structural Model of a Hirth Coupling

Hirth coupling transmits high torques in the rotating assemblies of compressors and turbines. Their mating surface contacts cause local changes in lateral shaft stiffness. This is affected by the teeth geometry, contact surface area, coupling preload, and surface finish at the contact faces. Industry practice ignores localized lateral flexibility from the Hirth coupling, or is guided by limited experience-based rules of thumb. The authors provide a novel modeling approach utilizing 3D solid finite elements which accounts for contact deformations, intricate interface teeth geometries, stress concentration, and surface finish. This provides an increased accuracy localized stiffness model for the Hirth coupling, to improve rotordynamic response predictions. Free-free natural frequencies of a test rotor including a Hirth coupling are experimentally measured. The rotor is instrumented with strain gauges for preload force measurements, and the Hirth coupling contacting surface profiles are measured with a stylus type surface profiler. A GW contact model is obtained from the measured surface profiles. An iterative computation algorithm is utilized to calculate Hirth coupling contact stiffness and contact pressure at the complex-shaped contact surfaces. Predicted and measured natural frequencies are compared vs. preload.

Klasterisasi Kasus Kekerasan Terhadap Anak dan Perempuan Berdasarkan Algoritma K-Means

Violence is action or threats against themselves alone, a group of people or community a group of people or community, loss psychologist, trauma, or deprivation of rights. District Karawang is on of the district that exist in the province of Jawa Barat. Violence that befell children and women in the area of Karawang bloom occurs, such as the lacj awareness of the victim to follow up cases that happened. The purpose of knowing the results of the cluster of cases of violence against children and women into three clusters are statterd in every sub-district in the District Karawang with category level of hardness low, medium or high in order that the government Karawang can provide treatment that is defferent and more targeted and focused on the results ot the analysis for each-each district. Data mining is the process of extracting data to obtain new information. In this study using CRIPS-DM methodology.Research is doing computation algorithm k-means clustering on the data of case of violence against children and women in 2016-2020. Results of testing using tools WEKA 3.8 earnded three cluster or the three categories of the level of violence that is cluster 0 there are 4 members who categorized the level of violence high, cluster 1 there are 2 members categorized the level of violence medium, and cluster 2 there are 24 members who categorized the level of violence low, the results of clustering is evaluated using equation testing purity measure, generate value purity 0,617, case that shows the cluster is quite good.

Implementation of the visual data processing algorithms for onboard computing units

According to the short analysis of modern experience of hardware and software for autonomous mobile robots a role of computer vision systems in the structure of those robots is considered. A number of configurations of onboard computers and implementation of algorithms for visual data capturing and processing are described. In original configuration space the «algorithms-hardware» plane is considered. For software designing the realtime vision system framework is used. Experiments with the computing module based on the Intel/Altera Cyclone IV FPGA (implementation of the histogram computation algorithm and the Canny's algorithm), with the computing module based on the Xilinx FPGA (implementation of a sparse and dense optical flow algorithms) are described. Also implementation of algorithm of graph segmentation of grayscale images is considered and analyzed. Results of the first experiments are presented.

Study of the micro-crack growth in the concrete material to predict its lifetime

The concrete always contains microstructures like micro-crack, voids, etc. These parameters affected the lifetime of materials. This article presents a computation algorithm to predict the lifetime of brittle materials like concrete which depends on the distribution of micro-crack in the materials. The proposed model is based on subcritical crack growth using the linear elastic fracture mechanics (LEFM) approach. The algorithm considers both tensile and shear fracturing. The proposed model was applied to a concrete sample under compressive loading for the prediction of a lifetime. The results showed a significant difference in failure zones and failure time under different magnitude compressive loadings and initial crack length.