scholarly journals Modeling and dynamic behavior of a discontinuous tourism-based social-ecological dynamical system

Filomat ◽  
2019 ◽  
Vol 33 (18) ◽  
pp. 5991-6004
Author(s):  
M. Behjaty ◽  
Z. Monfared
Keyword(s):  
Tourism Industry ◽  
System Stability ◽  
Dynamic Features ◽  
Negative Effects ◽  
Discontinuous System ◽  
Social Ecological ◽  
Different Types ◽  
Discontinuous Model ◽  
The Mathematical Model ◽  
Theoretical Results

In this paper we study a four-dimensional tourism-based social-ecological system including two different types of tourists, i.e., eco-tourists and mass-tourists. First we develop the mathematical model of this system, in order to make it more realistic. In fact, the negative effects of eco-tourists on the environment can not be always ignored. Therefore, we consider a discontinuous function for describing the damage induced by tourist activities to ecosystem quality. By introducing a discontinuous model in this way, we can provide a tool for better investigating the behavior of tourism phenomenon. We analyse the dynamic of the obtained discontinuous system, by using the theory of discontinuous dynamical systems. Moreover, in order to discuss about profitability, compatibility and sustainability of the obtained system, stability regions for that will be found. Furthermore by verifying tangent points of the discontinuous system, more dynamic features of eco and mas-tourists will be shown. In this regard, we determine some regions for existence of the collision of two tangent points for the system. Some numerical simulations are carried out to demonstrate our theoretical results. Here our numerical and theoretical achievements can provide useful information for analysing the tourism industry.

Theoretical and Experimental Researches Regarding the Influence of the Suspension Car Stiffness on the Dynamic Behavior of Vehicles

2016 ◽  
Vol 822 ◽  
pp. 36-43
Author(s):  
Dumitru Neagoe ◽  
Dumitru Bolcu ◽  
Loreta Simniceanu ◽  
Mario Trotea
Keyword(s):  
Mathematical Model ◽  
Dynamic System ◽  
Dynamic Behavior ◽  
Experimental Research ◽  
Experimental Results ◽  
Negative Effects ◽  
Experimental Researches ◽  
The Mathematical Model ◽  
Theoretical Results

In this paper the authors present the results of theoretical and experimental research in order to optimize suspension rigidity in case of Daewoo Nubira vehicle. The paper presents the mathematical model obtained by assimilating car with a dynamic system with 5 rigid solids with elastic and viscous linking between them. Theoretical results obtained based on this model and the experimental results are presented, and it is presented a solution to optimize suspension in order to remove the negative effects observed driving on gravel runways or damaged runaways. Theoretical results, compared with the experimental ones, allow us to say that it is possible to optimize suspension by analyzing specific parameters equivalent mathematical model.

scholarly journals STUDY OF THE PASTE-LIKE PROPELLANT COMBUSTION AT VARIOUS LOADING SCHEMES

2020 ◽  
pp. 89-101
Author(s):  
Viktor V. BURKIN ◽  
◽  
Aleksey S. D’YACHKOVSKIY ◽  
Aleksandr N. ISHCHENKO ◽  
Vladimir Z. KASIMOV ◽  
...  
Keyword(s):  
Maximum Pressure ◽  
Theoretical Studies ◽  
Powder Charge ◽  
Propellant Combustion ◽  
Dispersion Law ◽  
Different Types ◽  
Propellant Charge ◽  
The Mathematical Model ◽  
Experimental And Theoretical Studies ◽  
Theoretical Results

The experimental and theoretical studies of the paste-like propellant combustion in a model ballistic installation are implemented. The research is carried out using three masses of projectile assemblies and three types of the propellant charge. The paper presents two versions of the law of dispersion for paste-like propellants which allow accounting for the pressure on the front and acceleration of the projectile assembly with a traveling charge. The coefficients in the laws of dispersion are obtained. Using the mathematical model presented in this work, the gas-dynamic pictures of the shots when the propellants are applied as traveling charges are obtained for each dispersion law. Based on the results, a detailed study of the processes occurring with the traveling charge consisting of a model paste-like propellant is implemented for various shot arrangements. The discrepancy between theoretical results and the results obtained in the set of experiments is no more than 2% for the maximum pressure and no more than 1% for the muzzle velocity. The dispersion law accounting for the projectile assembly acceleration and traveling charge makes it possible to describe accurately the processes in the space behind the projectile for projectile assemblies of various masses and different types of granulated powder charge in terms of the model ballistic installation in the considered pressure range.

Modelling and Simulation of NO2 Dispersion Phenomenon in Atmosphere by Analytical-Experimental Methods

2008 ◽  
Vol 59 (10) ◽  
Author(s):  
Delia Perju ◽  
Harieta Pirlea ◽  
Gabriela-Alina Brusturean ◽  
Dana Silaghi-Perju ◽  
Sorin Marinescu
Keyword(s):  
Mathematical Model ◽  
Nitrogen Dioxide ◽  
Modeling And Simulation ◽  
Human Health ◽  
Experimental Methods ◽  
Negative Effects ◽  
Real Situation ◽  
Experimental Values ◽  
The Mathematical Model

The European laws and recently the Romanian ones impose more and more strict norms to the large nitrogen dioxide polluters. They are obligated to continuously improve the installations and products so that they limit and reduce the nitrogen dioxide pollution, because it has negative effects on the human health and environment. In this paper are presented these researches made within a case study for the Timi�oara municipality, regarding the modeling and simulation of the nitrogen dioxide dispersion phenomenon coming from various sources in atmosphere with the help of analytical-experimental methods. The mathematical model resulting from these researches is accurately enough to describe the real situation. This was confirmed by comparing the results obtained based on the model with real experimental values.

scholarly journals Not all biases are bad: equitable and inequitable biases in machine learning and radiology

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Mirjam Pot ◽  
Nathalie Kieusseyan ◽  
Barbara Prainsack
Keyword(s):  
Machine Learning ◽  
Human Error ◽  
Technical Problem ◽  
Social Dimension ◽  
Patient Treatment ◽  
Technical Solution ◽  
Negative Effects ◽  
Different Types ◽  
Human Decision

AbstractThe application of machine learning (ML) technologies in medicine generally but also in radiology more specifically is hoped to improve clinical processes and the provision of healthcare. A central motivation in this regard is to advance patient treatment by reducing human error and increasing the accuracy of prognosis, diagnosis and therapy decisions. There is, however, also increasing awareness about bias in ML technologies and its potentially harmful consequences. Biases refer to systematic distortions of datasets, algorithms, or human decision making. These systematic distortions are understood to have negative effects on the quality of an outcome in terms of accuracy, fairness, or transparency. But biases are not only a technical problem that requires a technical solution. Because they often also have a social dimension, the ‘distorted’ outcomes they yield often have implications for equity. This paper assesses different types of biases that can emerge within applications of ML in radiology, and discusses in what cases such biases are problematic. Drawing upon theories of equity in healthcare, we argue that while some biases are harmful and should be acted upon, others might be unproblematic and even desirable—exactly because they can contribute to overcome inequities.

The Perceived Impacts of Sport Tourism: An Urban Host Community Perspective

2010 ◽  
Vol 24 (2) ◽  
pp. 119-138 ◽  
Author(s):  
Nancy Hritz ◽  
Craig Ross
Keyword(s):  
Economic Benefits ◽  
Tourism Industry ◽  
Host Community ◽  
Environmental Benefits ◽  
Sport Tourism ◽  
Tourism Impacts ◽  
Different Types ◽  
Perceived Impacts ◽  
Negative Impacts ◽  
Social Environmental

Sport tourism is one of the fastest growing market segments in the tourism industry and is receiving increased attention for its social, environmental, and economic impacts upon destinations. Prior research in tourism impacts has tended to focus exclusively on tourism as a whole and does not differentiate among the different types of tourism that may be present in a destination. The purpose of this study was to examine how residents of Indianapolis, Indiana perceived the impacts sport tourism has upon their city. A total of 347 surveys were returned in a mailed questionnaire. Exploratory factor analysis revealed a four factor structure of social benefits, environmental benefits, economic benefits, and general negative impacts. Social and economic benefits were strong predictors for support for further sport tourism development revealing a strong identification with the advantages of sport tourism in their city such as an increased cultural identity and social interaction opportunities.

Shape-Tailored TiO2 Photocatalysts Obtained in the Presence of Different Types of Carbon Materials

2021 ◽  
Vol 21 (4) ◽  
pp. 2360-2367
Author(s):  
Krisztina Vajda ◽  
Klára Hernádi ◽  
Cosmin Coteţ ◽  
Gábor Kovács ◽  
Zsolt Pap
Keyword(s):  
Carbon Materials ◽  
Uv Light ◽  
Carbon Aerogel ◽  
Low Carbon ◽  
Negative Effects ◽  
Tio2 Photocatalysts ◽  
Uv Light Irradiation ◽  
Specific Morphology ◽  
Different Types ◽  
Photocatalytic Applications

Titania and carbon materials are intensively studied in composite materials including photocatalytic applications. Both positive and negative effects were described in the literature, including charge separation, adsorption enhancement and short-circuiting of the photoelectrons as well. In the present study a more sparsely investigated properties of carbon materials will be highlighted, namely their role as crystallization promoters for titania, during hydrothermal synthesis of the composites. Therefore, carbon nanotubes, carbon coils, activated carbon, graphite and carbon aerogel was used to identify the importance of carbon during the time dependent crystallization of titanium dioxide. The crystal phase composition, morphology, optical properties and photocatalytic activity was followed, and it was found that the anatase and rutile crystallization depended on the used carbon material. The morphology of the particles varied from single anatase sheet-like crystals to hierarchical microball-like structures, while in some cases no specific morphology was observed. Furthermore, it was found that despite the low carbon content (2 wt.%) and microcrystalline structure of TiO2 the composites were proven to be efficient in the degradation of Rhodamine B under UV light irradiation.

A prey–predator model and control of a nematodes pest using control in banana: Mathematical modeling and qualitative analysis

2021 ◽  
pp. 2150089
Author(s):  
Sudhakar Yadav ◽  
Vivek Kumar
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Local Stability ◽  
Detection Method ◽  
Initial Release ◽  
Pest Detection ◽  
Predator Model ◽  
And Control ◽  
The Mathematical Model ◽  
Theoretical Results

This study develops a mathematical model for describing the dynamics of the banana-nematodes and its pest detection method to help banana farmers. Two criteria: the mathematical model and the type of nematodes pest control system are discussed. The sensitivity analysis, local stability, global stability, and the dynamic behavior of the mathematical model are performed. Further, we also develop and discuss the optimal control mathematical model. This mathematical model represents various modes of management, including the initial release of infected predators as well as the destroying of nematodes. The theoretical results are shown and verified by numerical simulations.

scholarly journals The role of tourism awareness in developing accessible tourism

2020 ◽  
pp. 437-463
Author(s):  
طه مهدي محمود ◽  
حسين محمد علي أسد
Keyword(s):  
Young Children ◽  
Pregnant Women ◽  
Special Needs ◽  
The Elderly ◽  
Tourism Industry ◽  
Negative Effects ◽  
High Quality ◽  
Tourism Sector ◽  
Effective Contribution

Tourism awareness is one of the most important pillars that contribute to the development of the tourism industry in general, and the development of various tourism patterns in particular, and among those patterns are accessible tourism, because of its great importance in reducing the negative effects that may accompany the tourism industry by building educated tourism employees And be aware, knowledgeable and aware of the importance of the accomplishments and successes achieved by the tourism sector and the opportunities that this sector offers and economic opportunities that ultimately reflect on the members of society and the country. Perhaps the sensitivity of dealing with the categories of accessible tourism (those with special needs, the elderly, pregnant women, mothers for young children) need special type employees who possess a set of special skills and experiences in dealing with those groups to make the details of the tourist trip for the concerned individuals, the most important of which is accommodation (the hotel). And to achieve the best possibility to enjoy the tourist activity in general. This research aims to highlight on the role of tourism awareness for a sample of employees of the holy Karbala hotels and their effective contribution to achieve the development of soft tourism by providing high-quality services that reassure the targeted tourists and thus contribute to attract the largest number of them, which is greatly reflected in the development of tourism and making years Coming golden years for this tourist pattern, which is considered an ethical and human duty to care about and develop.

scholarly journals Development of the Russian tourism industry during the pandemic: an innovative approach

2021 ◽  
Vol 291 ◽  
pp. 05043
Author(s):  
Elena Oklirimeiiko ◽  
Sergey Chernov
Keyword(s):  
Tourism Industry ◽  
External Factors ◽  
Innovative Approach ◽  
Negative Effects ◽  
Factors Affecting ◽  
Travel And Tourism ◽  
Domestic Tourism ◽  
Event Tourism ◽  
Internal And External Factors ◽  
Tourism Services

The article deals with internal and external factors affecting the tourism industry in Russia as well as the ways of its promotion and development. The authors analyze decrease in sales in the tourism industry at the present period; the situation with provision of tourism services during the pandemic is identified and justified; the negative effects of the crisis are revealed. The authors also point out and present positive factors, which stimulate travel and tourism, including hotel business, catering, as well as resort business; the possibility of finding new ways to promote tourism industry is justified. The authors also analyze the main measures of tourism industry’s state support. The article considers dominant areas affecting the development of domestic tourism. The authors assess main aspects contributing to the development of event tourism. Conditions for the development of sports and event tourism are investigated and discussed; special features of tourism industry stimulation during the pandemic are presented. The authors consider and justify the possibility of restoring the tourist market.

D. 41,2,3,21: Titulierte Besitzarten, Erwerbsgründeund das unum genus possidendi

2013 ◽  
Vol 81 (3-4) ◽  
pp. 527-559
Author(s):  
Eric H. Pool
Keyword(s):  
Roman Law ◽  
Negative Effects ◽  
Distinctive Features ◽  
Depth Analysis ◽  
Different Types ◽  
The Law ◽  
The Many

D. 41,2,3,21 turns on the issue of how possessio is to be divided. Understanding its content presupposes making a distinction that was self-evident for the Roman jurist but has never been made by later scholars of Roman law. They do not distinguish the varying ‘causes’ of possession (pro emptore … pro suo) which mark different types of lawful possession, and the ‘causes’ of acquisition (causae adquirendi) which justify obtaining possesion as by an owner. Taking a legally valid sale as an example the distinctive features of (possessio) pro emptore in contrast to emptio are established as well as their relevance for procedural practice. In particular there are no less than six forms of action in the law of inheritance for which these features are relevant. Next, the many negative effects of failing to make this distinction are indicated. There follows an in depth analysis and interpretation of the main phrases in Paul’s text: (i) quod nostrum non est; (ii) causae ad­­quirendi, in particular iustae causae traditionis; (iii) unum genus possidendi; (iv) species infinitae.

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