New summation inequalities and their applications to discrete-time delay systems

This paper provides new summation inequalities in both single and double forms to be used in stability analysis of discrete-time systems with time-varying delays. The potential capability of the newly derived inequalities is demonstrated by establishing less conservative stability conditions for a class of linear discrete-time systems with an interval time-varying delay in the framework of linear matrix inequalities. The effectiveness and least conservativeness of the derived stability conditions are shown by academic and practical examples.Comment: 15 pages, 01 figur

Factors Affecting the Decision to Choose the Farmland Model in Le Tri Commune, Tri Ton District, An Giang Province, Vietnam

The study evaluated factors affecting the selection of agricultural farming models and advantages, difficulties, and opportunities in the implementation process to propose solutions to develop appropriate agricultural sustainable farming models. The study uses secondary and primary data through KIP interviews, focus group interviews, in-depth interviews, and farmer interviews. As a result, this study found education is an important factor affecting farmers in choosing their farming models and increasing agricultural production in their farmland. For most of the considered factors, the majority of Kinh people choose to evaluate the influence of the decision in choosing a farming model higher than another ethnic group (Khmer). Besides, the Khmer ethnic group accounts for a higher proportion of poor households (18.2%) than the Kinh group. Because of low economic conditions, decisions on agricultural production of Khmer ethnic groups are less assertive than that of the Kinh people. On the other hand, there is a serious shortage of water in the dry season in the highlands, cultivated mainly by rainwater, ethnic minority accounts for 53.36% of the whole commune population, educational level makes it difficult to apply modern techniques in production. Therefore, strengthening and mobilizing people, investing in building upland irrigation systems, and using effective land conversion are essential activities to be carried out to improve the efficiency of farming models to make sustainable agricultural production that can increase income and enhance the economic life of local people

On simultaneous diagonalization via congruence of real symmetric matrices

Simultaneous diagonalization via congruence (SDC) for more than two symmetric matrices has been a long standing problem. So far, the best attempt either relies on the existence of a semidefinite matrix pencil or casts on the complex field. The problem now is resolved without any assumption. We first propose necessary and sufficient conditions for SDC in case that at least one of the matrices is nonsingular. Otherwise, we show that the singular matrices can be decomposed into diagonal blocks such that the SDC of given matrices becomes equivalently the SDC of the sub-matrices. Most importantly, the sub-matrices now contain at least one nonsingular matrix. Applications to simplify some difficult optimization problems with the presence of SDC are mentioned

New H∞ control design for polytopic systems with mixed time-varying delays in state and input

This paper concerns with the problem of state-feedback H∞ control design for a class of linear systems with polytopic uncertainties and mixed time-varying delays in state and input. Our approach can be described as follows. We first construct a state-feedback controller based on the idea of parameter-dependent controller design. By constructing a new parameter-dependent Lyapunov-Krasovskii functional (LKF), we then derive new delay-dependent conditions in terms of linear matrix inequalities ensuring the exponential stability of the corresponding closed-loop system with a H∞ disturbance attenuation level. The effectiveness and applicability of the obtained results are demonstrated by practical examples

CURRENT SITUATION OF STUDENTS’ PSYCHOLOGICAL STATE BEFORE PRACTICAL COURSES’ FINAL EXAMS

The article aimed to determine the factors influencing students’ psychological state before the final exam of practical courses. The article used conventional scientific research methods in sports and physical training combined with psychological tests studied on fifty students at Ho Chi Minh City University of Physical Education and Sports (UPES). After reviewing related studies and consulting with experts, four tests were employed to assess the psychological state before the test of the research subjects. The results showed that students with a good psychological state to take the exam had good test results. Conversely, students with a feverish or lethargic state will have poor test results. The research results serve as the basis for proposing measures to adjust the psychological state before the exam, contributing to improving the learning results of students.  Article visualizations