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Objective: to investigate the cost efficiency of inventory management for publicly home appliance retail companies in the Brazilian market that operate, among other channels, with B2C (Business-to-Costumer) and discuss the possible impacts of e-commerce on inventory management. Method: the first step, construction of a descriptive summary of Magazine Luiza and seven other competitors; the second step, analysis of the optimal cost efficiency of companies' inventory management, through an integrated and dynamic model of Data Envelopment Analysis (DEA) and Optimal Control Theory (OCT). Amounts declared in the Quarterly Financial Statements between the fourth quarter of 2010 and the second quarter of 2018 were considered. Main Results: the discovery of best practices and the fact that, despite its extraordinary appreciation, Magazine Luiza was not a reference in inventory management and its costs during the analyzed period as a whole. Relevance/Originality: this article is an initial step to address the lack of studies on e-commerce for emerging markets and inventory management and its costs for e-commerce. Methodological Contributions: the proposition of a methodology that can be used by other researchers to assess the cost efficiency of inventory management and the impact of e-commerce, highlighting best practices.

Modern physics relies on two distinct fundamental theories, General Relativity and Quantum Mechanics. Both describe on one hand macroscopic and cosmological phenomena such as gravitational waves and black holes and on the other hand microscopic phenomena as superfluidity or the spin of particles. The unification of these two theories remains, so far, an unsolved problem. Interestingly, candidate Quantum Gravity theories predict a violation of the principles of General Relativity at different levels. It is, therefore, of a timely interest to detect violations of these principles and determine at which level they occur. Recent proposals to perform Einstein Equivalence Principle tests suggest a dramatic performance improvement using matter-wave atomic sensors. In this context, the design of the input states with well defined initial conditions is required. A state-of-the-art test of the universality of free fall (UFF) would, for example, require a control of positions and velocities at the level of 1 µm and 1 µm.s⁻¹, respectively. Moreover, sizerelated systematics constrain the maximum expansion rate possible to the 100 µm.s⁻¹level. This initial engineering of the input states has to be quite fast, of the order of few hundred ms at maximum, for the experiment’s duty cycle to be metrologically-relevant. In this thesis I developed optimized sequences based on the excitation of the center of mass and the size excitation of one or two cooled atomic sample as well as degenerated gases. Some sequences proposed in this thesis have already been implemented in experiments and significantly increase the control of atomic ensembles., La physique moderne repose sur deux théories fondamentales distinctes, la relativité générale et la mécanique quantique. Toutes les deux décrivent d’une part les phénomènes macroscopiques et cosmologiques tels que les ondes gravitationnelles et les trous noirs et d’autre part les phénomènes microscopiques comme la superfluidité ou le spin des particules. L’unification de ces deux théories reste, jusqu’à présent, un problème non résolu. Il est intéressant de noter que les différentes théories de gravité quantique prédisent une violation des principes de la relativité générale à différents niveaux.Il est donc hautement intéressant de détecter les violations de ces principes et de déterminer à quel niveau elles se produisent.De récentes propositions pour effectuer des tests du principe d’ équivalence d’Einstein suggèrent une amélioration spectaculaire des performances en utilisant des capteurs atomiques `a ondes de matière.Dans ce contexte, il est nécessaire de concevoir des états d’entrée de l’interferomètre avec des conditions initiales bien définies. Un test de pointe de l’universalité de la chute libre (Universality of FreeFall en anglais (UFF) ) nécessiterait, par exemple,un contrôle des positions et des vitesses avec une précision de l’ordre de 1 μm et 1 μm.s⁻¹ , respectivement.De plus, les systématiques liées à la taille du paquet d’ondes limitent le taux d’expansion maximum possible à 100 μm.s⁻¹. La création initiale des états d’entrée de l’interféromètre doit être assez rapide,de l’ordre de quelques centaines de ms au maximum,pour que le temps de cycle de l’expérience soit pertinent d’un point de vue métrologique. Dans cette thèse j’ai développé des séquences optimisées s’appuyant sur l’excitation du centre de masse et de la taille d’un ou plusieurs ensembles d’atomes refroidis ainsi que dégénérés. Certaines séquences proposé dans cette thèse ont déjà été implémenté dans des expériences augmentant de manière significative le contrôle des ensembles atomiques.

Using Optimal Control Theory (OCT), we design fast ramps for the controlled transport of Bose-Einstein condensates with atom chips' magnetic traps. These ramps are engineered in the context of precision atom interferometry experiments and support transport over large distances, typically of the order of 1 mm, i.e. about 1,000 times the size of the atomic clouds, yet with durations not exceeding 200 ms. We show that with such transport durations of the order of the trap period, one can recover the ground state of the final trap at the end of the transport. The performance of the OCT procedure is compared to that of a Shortcut-To-Adiabaticity (STA) protocol and the respective advantages / disadvantages of the OCT treatment over the STA one are discussed., Comment: 15 pages, 5 figures

Aim: If companies manage their inventory inefficiently, inventory costs can increase significantly due to shortages, overstocking, and risks. Inventory management is critical for company’s success which, in turn, impacts on countries’ development. This paper aims to investigate the efficiency of inventory control systems of companies from Brazil and Chile through Optimal Control Theory and Data Envelopment Analysis.Design/Research methods: Data was collected from Chilean and Brazilian companies covering different industries in which both countries are mostly dependent A new approach using OCT and DEA is applied for dealing with inventory, production, and demand in Dynamic DEA model to benchmark companies’ production-inventory systems.Conclusions/findings: The results show efficient companies among evaluated industries. Such companies are related mainly to Brazilian commerce and Chilean exports. Based on findings, it was possible to identify patterns and relationship among companies and its inventory management.Originality/value of the article: This paper fills a gap in studies including demand, production, and inventory in Dynamic DEA by using OCT to forewarn unrealistic results and observing companies’ behavior. Besides that, this approach is particularly useful for developing countries in this context, determining benchmarks for the most inefficient firms in each sector.Implications of the research: The results show (1) which companies should focus more on improving inventory management, (2) which companies should be used as benchmarks, and (3) it highlights the reasons of different performance of companies in each country.Limitations of the research: For future research, it is suggested including variables and analysis of social and environmental impacts.