Outage performance analysis of non-orthogonal multiple access with time-switching energy harvesting

In recent years, although non-orthogonal multiple access (NOMA) has shown its potentials thanks to its ability to enhance the performance of future wireless communication networks, a number of issues emerge related to the improvement of NOMA systems. In this work, we consider a half-duplex (HD) relaying cooperative NOMA network using decode-and-forward (DF) transmission mode with energy harvesting (Ell) capacity, where we assume the NOMA destination (D) is able to receive two data symbols in two continuous time slots which leads to the higher transmission rate than traditional relaying networks. To analyse EH, we deploy time-switching (TS) architecture to comprehensively study the optimal transmission time and outage performance at D. In particular, we are going to obtain closed-form expressions for outage probability (OP) with optimal TS ratio for both data symbols with both exact and approximate forms. The given simulation results show that the placement of the relay (R) plays an important role in the system performance.Web of Science253918

Géométrie de systèmes dynamiques stochastiques et modèles de second ordre pour les marchés financiers

Cette thèse est consacrée à l'étude des propriétés géométriques qualitatives de systèmes dynamiques stochastiques: leur symétries, la réduction et l'intégrabilité, avec des applications au problème de la modélisation des marchés financiers. Il se compose de quatre chapitres. Le chapitre 1 est une brève revue des notions de base de la théorie des systèmes dynamiques stochastiques (SDS) écrites sous la forme de Stratonovich, et aussi des systèmes Hamiltoniens. Le matériel de ce chapitre n'est pas nouvelle, et est inclus dans cette thèse pour la faire plus indépendante. Dans Chapitre 2, nous étudions le problème de la réduction de la SDS par rapport à une propre action d'un groupe de Lie. Il s'agit d'un problème important dans la théorie des systèmes dynamiques en général. Pour SDS, il a également été étudié par de nombreux auteurs. Diverses fameux processus stochastiques dans le calcul stochastique, par exemple, le processu de Bessel, peut être considéré comme un résultat de la réduction. Mais il y a encore quelques résultats relativement simples que nous n'avons pas trouvé dans la littérature et ainsi nous les écrivions dans Chapitre 2. En particulier, on montre que si un SDS n'est pas invariant mais seulement invariant un termes de diffusion par rapport à une action de groupe, alors nous pouvons faire encore la réduction. On donne les conditions nécessaires et suffisantes pour un SDS soit réductible (c-a-d projetable) par rapport à une submersion donné. Dans Chapitre 3, nous introduisons et étudions la notion d'intégrabilité de SDS. Ce notion d'intégrabilité se situe entre la notion d'intégrabilité pour déterministe classique systèmes et la notion d'intégrabilité des systèmes dynamiques quantiques. L'un des les résultats les plus fondamentaux de la théorie des systèmes dynamiques déterministe classique intégrable est l'existence des actions toriques de Liouville qui ont la propriété de conservation structurelle. Ces actions toriques de Liouville impliquent le comportement quasi-périodique des systèmes intégrables propres, nous permettront de faire la moyenne et la réduction (aussi pour les perturbations de systèmes intégrables), chercher des variables action-angle et faire quantification. Nous étendons ce résultat fondamental de la existence des actions toriques de Liouville avec la propriété de conservation structurelle vers les cas des SDS intégrable. Nous montrons aussi comment SDS intégrable sont naturellement liées au problème de métriques Riemanniennes avec des flots géodésiques intégrables, qui est un problème très intéressant dans la géométrie avec de nombreux nouveaux des résultats dans la littérature. Dans Chapitre 4, nous arguons que le premier ordre modèles (différentielle stochastique) de stock marchés, par exemple le fameux modèle de Black-Scholes, est conceptuellement pas correct pour le description de ce qui se passe sur les marchés financiers, même si elles peuvent être utilisé pour les prix des produits dérivés financiers. Des modèles plus réalistes de la marché doit être de second ordre, c-à-d en tenant compte à la fois les variables de prix et les variables de momentum. Nous développons dans ce chapitre deux modèles simples de second ordre, à savoir l'oscillateur stochastique et n-oscillateur contrainte stochastique, ce qui peut expliquer beaucoup de phénomènes sur les marchés. Une notion clé introduit dans ces modèles est l'énergie de la spéculation (dans l'analogie avec l'énergie physique), et nous prétendons que c'est cette énergie de la spéculation financière qui déplace le marchéThis thesis is devoted to a study of qualitative geometrical properties of stochastic dynamical systems, namely their symmetries, reduction and integrability, with applications to the problem of modelling of financial markets. It consists of four chapters. Chapter 1 is a brief review of basic notions from the theory of stochastic dynamical systems (SDS for short) written in Stratonovich form, and also Hamiltonian systems. The material in this chapter is not new, and is included in this thesis to make it self-contained. In Chapter 2, we study the problem of reduction of SDS with respect to a proper action of a Lie group. This is an important problem in the theory of dynamical systems in general. Various famous processes in stochastic calculus, e.g. the Bessel process, can be viewed as a result of reduction. But there are still some relatively simple results that we did not find in the literature and so we wrote them down in Chapter 2. In particular, we proved that if a SDS is not invariant but only diffusion-wise invariant with respect to a group action, then we can still do reduction. We also give necessary and sufficient conditions for a SDS to be reductible (i.e. projectable) with respect to a given submersion map. In Chapter 3, we introduce and study the notion of integrability of SDS. This integrability notion lies between the integrability notion for classical deterministic systems and the integrability notion for quantum dynamical systems. One of the most fundamental results in the theory of classical integrable deterministic dynamical systems is the existence of so called Liouville torus actions which have the structure-preserving property. Those Liouville torus actions imply the quasi-periodic behaviour of proper integrable systems, allow one to do averaging and reduction (also for perturbations of integrable systems), find action-angle variables, and do quantization. We extend this fundamental result about the existence of structure-preserving Liouville torus actions to the case of integrable SDS. We also show how integrable SDS are naturally related to the problem of Riemannian metrics with integrable geodesic flows, which is a very interesting problem in geometry with many recent results in the literature. In Chapter 4, we argue that first order (stochastic differential) models of the stock markets, e.g. the famous Black-Scholes model, is conceptually not correct for the description of what is happening in the financial markets, even though they can be used for pricing financial derivative products. More realistic models of the market must be of second order, i.e. taking into account both the price variables and the momentum variables. We develope in this chapter two simple second order models, namely the stochastic oscillator and the stochastic constrained n-oscillator, which can explain a lot of phenomena in the markets. A key notion introduced in these models is speculation energy (in analogy with physical energy), and we claim that it is this speculation energy which moves the financial market

The effects of national and international tourism on income inequality:evidence from Asia-Pacific economies

Purpose: This paper explores the effect of tourism (national and international) indicators on income inequality in a sample of 21 Asia Pacific economies. Design/methodology/approach: This study uses panel data set from 1995 to 2020 and employs panel autoregressive distributed lag (ARDL) method for the empirical investigation. Findings: The empirical findings from the panel ARDL models suggest that all of the considered tourism indicators have significant negative impacts on income inequalities. The results remain consistent with alternative indicators and methods. Social implications: The findings of this study will be critical for the policymakers to take effective measures to reduce the income inequality. Such measures could include promoting tourism in general, focusing on attracting international tourists or domestic tourists, and putting more weight on developing leisure or business tourism, which will boost the overall economic performance and alleviates inequalities in the society. Originality/value: This is the first study to consider various forms of tourism indicators to see their impact on income inequality in the Asia–Pacific region, and offers important implications for the policy actions

Examining the production and perceptions of public space in developing urban environment: an exploration of Ho Chi Minh City, Vietnam

Ph. D. ThesisIn developing countries, there is a growing trend for improving public space which transforms the built environment as well as raises the requirement for better public life. The driving forces to enhance experienced quality of urban spaces play significant role in urban design process. Moreover, according to the new life style and social contexts of market demanding, the current political systems and design styles have to be shifted and adapted so that the quality of these planning can meet the need of local citizens. Additionally, in the light of encouraging human interaction with urban environment, the design for public space raises the awareness of both public and private developers as well as local authorities and professionals in planning. The role of each of stakeholders during planning process may give the opportunities for these spaces to have an attractive appearance, exciting activities, and successful formulated design as well as involving all people. The study takes place around the feature of walkable streets as public spaces which associated to the discovered and investigation of two pedestrian streets in Ho Chi Minh City, Vietnam. This research contributes to the discussion that investigates the nature of planning and control in decision making process in the Southeast Asian’s socialism country. Furthermore, the study tends to explore social influences involving within the management of local authorities, the meaning of places and people’ perceptions on these public spaces. By using the combination of qualitative, quantitative and case study approaches, the research tends to answer how the triad (local authorities, planning professionals, and developers) deals with design planning for public spaces, the perceived of public space and the perception of users while these public spaces are being transformed. The result of this study not only contributes to the fields of urban design in Vietnam (which is very new in this country), but also it raises the awareness to the design for public space through the lens of all stakeholders involve in these places in the context of Southeast Asian cultures and different management system

A Fuzzy LQR PID Control for a Two-Legged Wheel Robot with Uncertainties and Variant Height

This paper proposes a fuzzy LQR PID control for a two-legged wheeled balancing robot for keeping stability against uncertainties and variant heights. The proposed control includes the fuzzy supervisor, LQR, PID, and two calibrations. The fuzzy LQR is conducted to control the stability and motion of the robot while its posture changes with respect to time. The fuzzy supervisor is used to adjust the LQR control according to the robotic height. It consists of one input and one output. The input and output have three membership functions, respectively, to three postures of the robot. The PID control is used to control the posture of the robot. The first calibration is used to compensate for the bias value of the tilting angle when the robot changes its posture. The second calibration is applied to compute the robotic height according to the hip angle. In order to verify the effectiveness of the proposed control, a practical robot with the variant height is constructed, and the proposed control is embedded in the control board. Finally, two experiments are also conducted to verify the balancing and moving ability of the robot with the variant posture

Interdisciplinary education in the context of protection of water resources: A case study in Vietnam

The incorporation of interdisciplinary education, a topic of significant global interest, is increasingly being recognized as a key aspect of educational innovation in Vietnam. This recognition extends to several fields, including STEM (Science, Technology, Engineering, and Mathematics) education.This research aims to design and implement a STEM situation associated with the context of water protection in Vietnam for 10th-grade students in which students mobilize the knowledge of Physics (specific gravity, Archimedes' principle) and Mathematics (volume) to design a salinometer. This device measures the salinity of the water. The research methodology is based on the observed increase in saline levels in the coastal regions of Vietnam in recent years, which has had a substantial impact on agriculture and the livelihoods of millions of people. This methodology aims to provide realistic scenarios for students to address and resolve these problems. A total of forty students in the 10th grade were involved in a teaching situation that consisted of five distinct phases. Forty 10th-grade students participated in a teaching situation conducted in five phases. The results showed that the situation helped students strengthen and connect their physics and mathematics knowledge, create a vibrant learning atmosphere, enhance communication, and develop problem-solving competency. Furthermore, the teaching situation also needs to be revised regarding the measurement practices of Vietnamese students. The situation contributes to educating students' awareness of current events, protecting Vietnamese water resources, and the importance of sustainable development. In addition, we can use the same teaching process as in this research to develop other STEM teaching situations