134 research outputs found
The influence of parameters of consecutive speed control humps ...
This paper is aimed at analyzing the chaotic vibration of a vehicle passing the consecutive speed control humps (SCHs) on a highway. A consecutive SCHs-speed coupling excitation function is presented. The chaotic vibration of nonlinear vehicle is studied by numerical simulation under a 2-DOF nonlinear vehicle suspension model. The chaotic vibration excited by the consecutive SCHs with different parameters is analyzed. Simulation results demonstrate that the chaotic motion may occur as the vehicle moves over a series of the consecutive SCHs. Furthermore, chaotic motion can be inhibited reasonably and effectively by proper adjustment of parameters of the consecutive SCHs
Approximate finite-dimensional ODE temperature model for microwave heating
In this paper, a finite-dimensional ordinary differential equation (ODE) model is proposed for predicting the temperature profile with microwave heating to accomplish lower computing complexity. The traditional parabolic partial different equation (PDE) model with integrating Maxwell's equation and heat transport equation is not suitable for designing the on-line controller. Based on the obstruction, using an auxiliary function derives an intermediate model, which is analyzed and discussed for model reduction by employing the parameter separation method and Galerkin's method. The simulation experiments on one-dimensional waveguide and cavity demonstrate that the proposed approximate model is effective
The influence of parameters of consecutive speed control humps ...
This paper is aimed at analyzing the chaotic vibration of a vehicle passing the consecutive speed control humps (SCHs) on a highway. A consecutive SCHs-speed coupling excitation function is presented. The chaotic vibration of nonlinear vehicle is studied by numerical simulation under a 2-DOF nonlinear vehicle suspension model. The chaotic vibration excited by the consecutive SCHs with different parameters is analyzed. Simulation results demonstrate that the chaotic motion may occur as the vehicle moves over a series of the consecutive SCHs. Furthermore, chaotic motion can be inhibited reasonably and effectively by proper adjustment of parameters of the consecutive SCHs
Controlling nutritional status score is associated with renal progression, cardiovascular events, and all-cause mortality in biopsy-proved diabetic kidney disease
Background: The Controlled Nutritional Status (CONUT) score, calculated from albumin, total cholesterol, and lymphocyte count, is a useful indicator for immune-nutritional assessment and is associated with the prognosis of various diseases. However, its relationship with renal outcomes, cardiovascular disease (CVD), and all-cause mortality in patients with diabetic kidney disease is unclear.Methods: This retrospective single-center study enrolled 336 patients with biopsy-confirmed diabetic kidney disease from August 2009 to December 2018. The outcomes were progression to end-stage renal disease (ESRD), CVD events, and death. Univariate and multivariate Cox regression analyses were performed to estimate the association between confounding factors and outcomes. The Kaplan-Meier curve was used to compare the outcomes of the patients according to the median CONUT score. The area under the curve (AUC) evaluated with time-dependent receiver operating characteristics was used to test discriminative power of COUNT score.Results: During a median follow-up period of 5.1 years. The Kaplan-Meier analysis showed that patients in the high CONUT group (CONUT score > 3) had a significantly higher incidence of ESRD, CVD events, and all-cause mortality than those in the low CONUT group (CONUT score ≤ 3). The multivariate COX regression analysis indicated that, The CONUT score was an independent predictor of ESRD (hazards ration [HR] = 1.129, 95% confidence interval [CI] 1.037-1.228, p = 0.005), CVD events (HR = 1.159, 95% CI 1.057-1.271, p = 0.002), and all-cause mortality (HR = 1.299, 95% CI 1.143-1.478, p < 0.001).Conclusion: The CONUT score is an independent risk factor for ESRD, CVD events, and overall death in patients with diabetic kidney disease
A Robust Collaborative Filtering Approach Based on User Relationships for Recommendation Systems
Personalized recommendation systems have been widely used as an effective way to deal with information overload. The common approach in the systems, item-based collaborative filtering (CF), has been identified to be vulnerable to “Shilling” attack. To improve the robustness of item-based CF, the authors propose a novel CF approach based on the mostly used relationships between users. In the paper, three most commonly used relationships between users are analyzed and applied to construct several user models at first. The DBSCAN clustering is then utilized to select the valid user model in accordance with how the models benefit detecting spam users. The selected model is used to detect spam user group. Finally, a detection-based CF method is proposed for the calculation of item-item similarities and rating prediction, by setting different weights for suspicious spam users and normal users. The experimental results demonstrate that the proposed approach provides a better robustness than the typical item-based kNN (k Nearest Neighbor) CF approach
Defending against the Advanced Persistent Threat: An Optimal Control Approach
The new cyberattack pattern of advanced persistent threat (APT) has posed a serious threat to modern society. This paper addresses the APT defense problem, that is, the problem of how to effectively defend against an APT campaign. Based on a novel APT attack-defense model, the effectiveness of an APT defense strategy is quantified. Thereby, the APT defense problem is modeled as an optimal control problem, in which an optimal control stands for a most effective APT defense strategy. The existence of an optimal control is proved, and an optimality system is derived. Consequently, an optimal control can be figured out by solving the optimality system. Some examples of the optimal control are given. Finally, the influence of some factors on the effectiveness of an optimal control is examined through computer experiments. These findings help organizations to work out policies of defending against APTs
From similarity perspective: a robust collaborative filtering approach for service recommendations
- …