scholarly journals The Bifurcation and Control of a Single-Species Fish Population Logistic Model with the Invasion of Alien Species

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Yi Zhang ◽  
Qiaoling Zhang ◽  
Jinghao Li ◽  
Qingling Zhang
Keyword(s):  
Alien Species ◽  
Logistic Model ◽  
Singular System ◽  
Sufficient Conditions ◽  
Single Species ◽  
Fish Population ◽  
Point Of View ◽  
Practical Significance ◽  
Singularity Induced Bifurcation ◽  
And Control

The objective of this paper is to study systematically the bifurcation and control of a single-species fish population logistic model with the invasion of alien species based on the theory of singular system and bifurcation. It regardsSpartina anglicaas an invasive species, which invades the fisheries and aquaculture. Firstly, the stabilities of equilibria in this model are discussed. Moreover, the sufficient conditions for existence of the trans-critical bifurcation and the singularity induced bifurcation are obtained. Secondly, the state feedback controller is designed to eliminate the unexpected singularity induced bifurcation by combining harvested effort with the purification capacity. It obviously inhibits the switch of population and makes the system stable. Finally, the numerical simulation is proposed to show the practical significance of the bifurcation and control from the biological point of view.

H∞ control of T–S fuzzy fish population logistic model with the invasion of alien species

2016 ◽  
Vol 173 ◽  
pp. 724-733 ◽  
Author(s):  
Yi Zhang ◽  
Qiaoling Zhang ◽  
Guofeng Zhang
Keyword(s):  
Alien Species ◽  
Logistic Model ◽  
Fish Population

On One Approach to Assessing the Efficiency of Inspection and Control Activities

2020 ◽  
pp. 63-68
Author(s):  
M.I. Lukyanchikov ◽  
◽  
V.V. Lesnykh ◽  
◽  
Keyword(s):  
Methodological Approach ◽  
Point Of View ◽  
Industrial Safety ◽  
Practical Significance ◽  
Scientific Publications ◽  
Basic Model ◽  
Hazardous Production ◽  
And Control ◽  
Inspection Control ◽  
Production Facilities

The problem is reviewed concerning the efficiency of inspection control activities assessment. The importance of using a risk-oriented approach for the transition to proactive methods of ensuring the production safety of hazardous production facilities is noted. It is concluded that it is necessary to develop the basic model in terms of using the value of prevented damage as one of the efficiency indicators. The analysis is made concerning the scientific publications from the point of view of the possibility and feasibility of using the Heinrich-Berd pyramid when justifying activities on ensuring industrial safety. The examples of using this approach in solving various practical tasks is given in the article. A methodological approach is proposed related to the assessment of prevented damage as one of the indicators of the efficiency of inspection control activities using the methodology of building the Heinrich-Berd pyramid. In addition to the existing 4-level classification of events in the field of industrial safety, it is recommended to introduce level 5 related to the identification of inconsistencies identified as the result of inspection and control activities. Identified inconsistencies are prerequisites for the events of level 4 of classification. It is assumed that the elimination of the identified inconsistencies (level 5) can potentially lead to the prevention of events at levels 1–4. The formula is proposed for calculating the prevented damage (direct and indirect) considering the ratio between the events of different levels and the level of elimination of the identified inconsistencies. Estimated calculations of the total prevented damage to the hazardous production facilities in the gas industry were performed. The calculations showed the adequacy and practical significance of the proposed approach. This approach, of course, requires testing and confirmation of the assumptions made, but in general shows that the value of the prevented damage can be estimated and used as one of the indicators of the efficiency of the inspection and control activities.

scholarly journals Stochastic Permanence, Stationary Distribution and Extinction of a Single-Species Nonlinear Diffusion System with Random Perturbation

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Li Zu ◽  
Daqing Jiang ◽  
Donal O’Regan
Keyword(s):  
Numerical Simulation ◽  
Stationary Distribution ◽  
Nonlinear Diffusion ◽  
Logistic Model ◽  
Random Perturbation ◽  
Sufficient Conditions ◽  
Single Species ◽  
Unique Positive Solution ◽  
Stochastic Perturbations ◽  
Stochastic Permanence

We analyze the influence of stochastic perturbations on a single-species logistic model with the population’s nonlinear diffusion amongnpatches. First, we show that this system has a unique positive solution. Then we obtain sufficient conditions for stochastic permanence and persistence in mean, stationary distribution, and extinction. Finally, we illustrate our conclusions through numerical simulation.

Specimen Preparation for Clinical Applications of X-Ray Microanalysis

1990 ◽  
Vol 48 (2) ◽  
pp. 328-329
Author(s):  
J.D. Shelburne ◽  
G.M. Roomans
Keyword(s):  
Carbon Coating ◽  
Clinical Applications ◽  
Point Of View ◽  
Practical Significance ◽  
Sweat Test ◽  
Specimen Preparation ◽  
Tissue Preparation ◽  
X Ray ◽  
Gallbladder Stones ◽  
Clinical Problems

Proper preparative procedures are a prerequisite for the validity of the results of x-ray microanalysis of biological tissue. Clinical applications of x-ray microanalysis are often concerned with diagnostic problems and the results may have profound practical significance for the patient. From this point of view it is especially important that specimen preparation for clinical applications is carried out correctly.Some clinical problems require very little tissue preparation. Hair, nails, and kidney and gallbladder stones may be examined and analyzed after carbon coating. High levels of zinc or copper in hair may be indicative of dermatological or systemic diseases. Nail clippings may be analyzed (as an alternative to the more conventional sweat test) to confirm a diagnosis of cystic fibrosis. X-ray microanalysis in combination with scanning electron microscopy has been shown to be the most reliable method for the identification of the components of kidney or gallbladder stones.A quantitatively very important clinical application of x-ray microanalysis is the identification and quantification of asbestos and other exogenous particles in lung.

DEVELOPMENT OF COMPUTERIZED MONITORING AND CONTROL SYSTEM OF THE MOBILE ROBOT’S POSITIONING ON LARGE FERROMAGNETIC SURFACES BASED ON INTELLIGENT TECHNIQUES. COMPLEX OF TASKS OF MONITORING AND AUTOMATIC CONTROL OF MOBILE

2019 ◽  
pp. 37-47
Author(s):  
Yao Yueqin ◽  
Oleksiy Kozlov ◽  
Oleksandr Gerasin ◽  
Galyna Kondratenko
Keyword(s):  
Automatic Control ◽  
Point Of View ◽  
Monitoring And Control ◽  
Large Area ◽  
Monitoring And Control System ◽  
Technical Parameters ◽  
Automatic Control Systems ◽  
Current State ◽  
Computerized Monitoring ◽  
And Control

Analysis and formalization of the monitoring and automatic control tasks of the MR for the movement and execution of various types of technological operations on inclined and vertical ferromagnetic surfaces are obtained. Generalized structure of mobile robotic complex is shown with main subsystems consideration. Critical analysis of the current state of the problem of development of universal structures of mobile robots (MRs) for the various types of technological operations execution and elaborations of computerized systems for monitoring and control of MR movement is done. In particular, wheeled, walked and crawler type MRs with pneumatic, vacuum-propeller, magnetic and magnetically operated clamping devices to grip with vertical and ceiling surfaces are reviewed. The constructive features of the crawler MR with magnetic clamping devices capable of moving along sloping ferromagnetic surfaces are considered. The basic technical parameters of the MR are shown for the further synthesis of computerized monitoring and automatic control systems. Formalization of the tasks of monitoring and control of the MR positioning at the processing of large area ferromagnetic surfaces is considered from the point of view of control theory.

ABOUT UNIFORMITY OF THE PHENOMENOLOGY AND THE MATHEMATICAL DESCRIPTION OF SO-CALLED « JOINED» ACTION OF HAZARDS AND COMBINED TOXICITY (ON THE EXAMPLE OF A COMBIBATION OF THE FLUORIDE AND THE STATIC MAGNETIC FIELD)

2016 ◽  
pp. 13-20
Author(s):  
B. A. Katsnelson ◽  
M. P. Sutunkova ◽  
N. A. Tsepilov ◽  
V. G. Panov ◽  
A. N. Varaksin ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Static Magnetic Field ◽  
Point Of View ◽  
Whole Body ◽  
Surface Model ◽  
Combined Toxicity ◽  
Fluoride Solution ◽  
Adverse Action ◽  
Biochemical Indices ◽  
And Control

Sodium fluoride solution was injected i.p. to three groups of rats at a dose equivalent to 0.1 LD50 three times a week up to 18 injections. Two out of these groups and two out of three groups were sham-injected with normal saline and were exposed to the whole body impact of a 25 mT static magnetic field (SMF) for 2 or 4 hr a day, 5 times a week. Following the exposure, various functional and biochemical indices were evaluated along with histological examination and morphometric measurements of the femur in the differently exposed and control rats. The mathematical analysis of the combined effects of the SMF and fluoride based on the a response surface model demonstrated that, in full correspondence with what we had previously found for the combined toxicity of different chemicals, the combined adverse action of a chemical plus a physical agent was characterized by a tipological diversity depending not only on particular effects these types were assessed for but on the dose and effect levels as well. From this point of view, the indices for which at least one statistically significant effect was observed could be classified as identifying (I) mainly single-factor action; (II) additive unidirectional action; (III) synergism (superadditive unidirectional action); (IV) antagonism, including both subadditive unidirectional action and all variants of contradirectional action.

scholarly journals Survival analysis of a stochastic delay single-species system in polluted environment with psychological effect and pulse toxicant input

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Xiangjun Dai ◽  
Suli Wang ◽  
Weizhi Xiong ◽  
Ni Li
Keyword(s):  
Sufficient Conditions ◽  
Single Species ◽  
Threshold Value ◽  
Psychological Effect ◽  
Polluted Environment ◽  
Population System ◽  
Stochastic Delay ◽  
Species Population ◽  
The Mean ◽  
Single Species Population

Abstract We propose and study a stochastic delay single-species population system in polluted environment with psychological effect and pulse toxicant input. We establish sufficient conditions for the extinction, nonpersistence in the mean, weak persistence, and strong persistence of the single-species population and obtain the threshold value between extinction and weak persistence. Finally, we confirm the efficiency of the main results by numerical simulations.

scholarly journals A Multi-Timescale Bilinear Model for Optimization and Control of HVAC Systems with Consistency

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 400 ◽  
Author(s):  
Zelin Nie ◽  
Feng Gao ◽  
Chao-Bo Yan
Keyword(s):  
Optimization Model ◽  
Air Conditioning ◽  
State Of The Art ◽  
Hvac Systems ◽  
Practical Significance ◽  
Hvac System ◽  
Bilinear Model ◽  
Optimization And Control ◽  
And Control ◽  
Slow Timescale

Reducing the energy consumption of the heating, ventilation, and air conditioning (HVAC) systems while ensuring users’ comfort is of both academic and practical significance. However, the-state-of-the-art of the optimization model of the HVAC system is that either the thermal dynamic model is simplified as a linear model, or the optimization model of the HVAC system is single-timescale, which leads to heavy computation burden. To balance the practicality and the overhead of computation, in this paper, a multi-timescale bilinear model of HVAC systems is proposed. To guarantee the consistency of models in different timescales, the fast timescale model is built first with a bilinear form, and then the slow timescale model is induced from the fast one, specifically, with a bilinear-like form. After a simplified replacement made for the bilinear-like part, this problem can be solved by a convexification method. Extensive numerical experiments have been conducted to validate the effectiveness of this model.

Cyclopean Vision, Size Estimation, and Presence in Orthostereoscopic Images

2001 ◽  
Vol 10 (3) ◽  
pp. 312-330 ◽  
Author(s):  
Bernard Harper ◽  
Richard Latto
Keyword(s):  
Visual System ◽  
Three Dimensional ◽  
Point Of View ◽  
Psychophysical Experiment ◽  
Size Estimation ◽  
Human Form ◽  
Image Capture ◽  
Series Of Experiments ◽  
Abstract Shapes ◽  
And Control

Stereo scene capture and generation is an important facet of presence research in that stereoscopic images have been linked to naturalness as a component of reported presence. Three-dimensional images can be captured and presented in many ways, but it is rare that the most simple and “natural” method is used: full orthostereoscopic image capture and projection. This technique mimics as closely as possible the geometry of the human visual system and uses convergent axis stereography with the cameras separated by the human interocular distance. It simulates human viewing angles, magnification, and convergences so that the point of zero disparity in the captured scene is reproduced without disparity in the display. In a series of experiments, we have used this technique to investigate body image distortion in photographic images. Three psychophysical experiments compared size, weight, or shape estimations (perceived waist-hip ratio) in 2-D and 3-D images for the human form and real or virtual abstract shapes. In all cases, there was a relative slimming effect of binocular disparity. A well-known photographic distortion is the perspective flattening effect of telephoto lenses. A fourth psychophysical experiment using photographic portraits taken at different distances found a fattening effect with telephoto lenses and a slimming effect with wide-angle lenses. We conclude that, where possible, photographic inputs to the visual system should allow it to generate the cyclopean point of view by which we normally see the world. This is best achieved by viewing images made with full orthostereoscopic capture and display geometry. The technique can result in more-accurate estimations of object shape or size and control of ocular suppression. These are assets that have particular utility in the generation of realistic virtual environments.

Sign in / Sign up

Export Citation Format

Share Document