Results 11 to 20 of about 55 (39)

Segmented Linear Regression Models for Assessing Change in Retrospective Studies in Healthcare. [PDF]

Comput Math Methods Med, 2019
Introduction. In retrospective studies, the effect of a given intervention is usually evaluated by using statistical tests to compare data from before and after the intervention. A problem with this approach is that the presence of underlying trends can lead to incorrect conclusions. This study aimed to develop a rigorous mathematical method to analyse
Valsamis EM, Ricketts D, Husband H, Rogers BA.   +3 more
europepmc   +2 more sources

Large Deviation Rates for the Continuous‐Time Supercritical Branching Processes with Immigration

Journal of Mathematics, Volume 2022, Issue 1, 2022., 2022
Let {Y(t); t ≥ 0} be a supercritical continuous‐time branching process with immigration; our focus is on the large deviation rates of Y(t) and thus extending the results of the discrete‐time Galton–Watson process to the continuous‐time case. Firstly, we prove that Z(t) = e−mt[Y(t) − ((em(t + 1) − 1)/(em − 1))ea+m] is a submartingale and converges to a ...
Juan Wang, Xiaojuan Wang, G. Muhiuddin
wiley   +1 more source

Stock Prediction Based on Optimized LSTM and GRU Models

Scientific Programming, Volume 2021, Issue 1, 2021., 2021
Stock market prediction has always been an important research topic in the financial field. In the past, inventors used traditional analysis methods such as K‐line diagrams to predict stock trends, but with the progress of science and technology and the development of market economy, the price trend of a stock is disturbed by various factors.
Ya Gao, Rong Wang, Enmin Zhou, Punit Gupta   +3 more
wiley   +1 more source

LMI‐Based Analysis and Stabilization of Nonlinear Descriptors with Multiple Delays via Delayed Nonlinear Controller Schemes

Mathematical Problems in Engineering, Volume 2021, Issue 1, 2021., 2021
This paper presents a convex approach for nonlinear descriptor systems with multiple delays; it allows designing delayed nonlinear controllers such that the closed‐loop system holds exponential estimates for convergence. The proposal takes advantage of an equivalent convex representation of the given descriptor model together with Lyapunov‐Krasovskii ...
Javier Adrián Romero-Vega, Raúl Villafuerte-Segura, Víctor Estrada-Manzo, Maria Patrizia Pera   +3 more
wiley   +1 more source

Actuator Fault Detection for Discrete‐Time Descriptor Systems via a Convex Unknown Input Observer with Unknown Scheduling Variables

Mathematical Problems in Engineering, Volume 2021, Issue 1, 2021., 2021
This paper presents actuator fault detection of discrete‐time nonlinear descriptor systems by means of nonlinear unknown input observers. The approach is based on the exact factorization of the estimation error in order to overcome the well‐known problem of unmeasurable scheduling variables within the observation of convex models, thus avoiding the use
Javier Martinez, Braulio Aguiar, Víctor Estrada-Manzo, Miguel Bernal, Zhifeng Dai   +4 more
wiley   +1 more source

Graph‐Based Analysis of RNA Secondary Structure Similarity Comparison

Complexity, Volume 2021, Issue 1, 2021., 2021
In organisms, ribonucleic acid (RNA) plays an essential role. Its function is being discovered more and more. Due to the conserved nature of RNA sequences, its function mainly depends on the RNA secondary structure. The discovery of an approximate relationship between two RNA secondary structures helps to understand their functional relationship better.
Lina Yang, Yang Liu, Xiaochun Hu, Patrick Wang, Xichun Li, Jun Wu, Jia Wu   +6 more
wiley   +1 more source

DOA Estimation with Spatial Spread Vector‐Sensor Array Based on Biquaternion MUSIC

Wireless Communications and Mobile Computing, Volume 2021, Issue 1, 2021., 2021
The mutual coupling among various components of the collocated crossdipole (CCD) vector‐sensor is severe, and its application is greatly limited. The spatial spread dipole (SSD) vector‐sensor can avoid this problem, but the multiple signal classification (MUSIC) algorithm for the SSD array is rarely developed.
Qinyu Zhu, Guimei Zheng, Chen Chen, Qian Guo, Abdul Basit   +4 more
wiley   +1 more source

Global Analysis of a Delayed Impulsive Lotka‐Volterra Model with Holling III Type Functional Response

Mathematical Problems in Engineering, Volume 2015, Issue 1, 2015., 2015
A delayed impulsive Lotka‐Volterra model with Holing III type functional response was established. With the help of Mawhin’s Continuation Theorem in coincidence degree theory, a sufficient condition is found for the existence of positive periodic solutions of the system under consideration. By applying the comparison theorem and constructing a suitable
Hui Wang, Xiaomin Hu, Zhixing Hu, Fucheng Liao, Shaofan Li   +4 more
wiley   +1 more source

Joint Estimation of DOA and Polarization with CLD Pair Cylindrical Array Based on Quaternion Model

Mathematical Problems in Engineering, Volume 2014, Issue 1, 2014., 2014
This paper proposes a quaternion‐ESPRIT algorithm for closed‐form estimation of direction of arrival (DOA) and polarization, using a cylindrical conformal array configuration. First, the array steering vector and the elevation are estimated using a quaternion eigenvalue decomposition of the data covariance matrix.
Guibao Wang, Haihong Tao, Lanmei Wang, Cao Zeng, Gradimir Milovanović   +4 more
wiley   +1 more source

Coordination Scheme for Restructuring Business Operation of the Single Period Newsvendor Problem

Mathematical Problems in Engineering, Volume 2013, Issue 1, 2013., 2013
This paper presents a coordination scheme for a single period newsvendor problem when both supplier and retailer of the supply chain agree to change the business operation from a market decision power sharing system (Model 1) to a unique decision maker system (Model 2).
Chiuh-Cheng Chyu, I-Ping Huang, Yi-Chung Hu   +2 more
wiley   +1 more source