Cooperation and profit allocation in distribution chains

We study the coordination of actions and the allocation of profit in distribution chains under decentralized control. We consider distribution chains in which a single supplier supplies goods for replenishment of stocks of several retailers who, in turn, sell these goods to their own separate markets. The goal of the supplier and the retailers is to maximize their individual profits. Since the optimal joint profit under centralized control is larger than the sum of the individual optimal profits under decentralized control, cooperation among firms by means of coordination of actions may improve individual profits. The effects of cooperation are studied by means of cooperative games. For each distribution chain we define a corresponding cooperative game and study its properties. Among others we show that such games are balanced. Based on the nice core structure a stable solution concept for these games is proposed and its properties are interpreted in terms of the underlying distribution chain. \u

Supply chain collaboration

In the past, research in operations management focused on single-firm analysis. Its goal was to provide managers in practice with suitable tools to improve the performance of their firm by calculating optimal inventory quantities, among others. Nowadays, business decisions are dominated by the globalization of markets and increased competition among firms. Further, more and more products reach the customer through supply chains that are composed of independent firms. Following these trends, research in operations management has shifted its focus from single-firm analysis to multi-firm analysis, in particular to improving the efficiency and performance of supply chains under decentralized control. The main characteristics of such chains are that the firms in the chain are independent actors who try to optimize their individual objectives, and that the decisions taken by a firm do also affect the performance of the other parties in the supply chain. These interactions among firms’ decisions ask for alignment and coordination of actions. Therefore, game theory, the study of situations of cooperation or conflict among heterogenous actors, is very well suited to deal with these interactions. This has been recognized by researchers in the field, since there are an ever increasing number of papers that applies tools, methods and models from game theory to supply chain problems

Transient convective instabilities in directional solidification

We study the convective instability of the melt during the initial transient in a directional solidification experiment in a vertical configuration. We obtain analytically the dispersion relation, and perform an additional asymptotic expansion for large Rayleigh number that permits a simpler analytical analysis and a better numerical behavior. We find a transient instability, i.e. a regime in which the system destabilizes during the transient whereas the final unperturbed steady state is stable. This could be relevant to growth mode predictions in solidification.Comment: 28 pages, 5 figures. The following article has been accepted for publication in Physics of Fluids. After it is published, it will be found at http://pof.aip.or

Optical Supersymmetry in the Time Domain

Originally emerged within the context of string and quantum field theory, and later fruitfully extrapolated to photonics, the algebraic transformations of quantum-mechanical supersymmetry were conceived in the space realm. Here, we introduce a paradigm shift, demonstrating that Maxwell's equations also possess an underlying supersymmetry in the time domain. As a result, we obtain a simple analytic relation between the scattering coefficients of a large variety of time-varying optical systems and uncover a wide new class of reflectionless, three dimensional, all-dielectric, isotropic, omnidirectional, polarization-independent, non-complex media. Temporal supersymmetry is also shown to arise in dispersive media supporting temporal bound states, which allows engineering their momentum spectra and dispersive properties. These unprecedented features define a promising design platform for free-space and integrated photonics, enabling the creation of a number of novel reconfigurable reflectionless devices, such as frequency-selective, polarization-independent and omnidirectional invisible materials, compact frequency-independent phase shifters, broadband isolators, and versatile pulse-shape transformers

Application for Sign Language Education for People with Mental Handicap

Tato bakalářská práce popisuje vývoj aplikace pro výuku znaku do řeči pro osoby s mentálním postižením. Práce popisuje základní principy teorie počítačové terapie, ze které vychází, a cílovou skupinu uživatelů. Aplikace je vyvíjena pro operační systém Android a iOS, které jsou v práci stručně představeny. Následuje analýza již existujících aplikací podobného zaměření, návrh nové aplikace a implementace tohoto návrhu. V závěru práce bude popsána odezva uživatelů s mentálním postižením a jejich lektorů a navrhne se plán na možné rozšíření aplikace do budoucna.The thesis describes creation and development of an application for sign language education for people with mental handicap. The thesis describes basic principles of the theory of computer therapy, which is the basis for the application, as well as a target group of users. The application is developed for the operation systems Android and iOS, which are briefly introduced in this work. Then there is an analysis of some already existing applications of this kind, a design of a new application, and implementation of the design. At the end, there is a feedback by three application users with mental handicap and their lectors, and there is also a plan for the further extension of the application proposed.

Complex dynamics in double-diffusive convection

The dynamics of a small Prandtl number binary mixture in a laterally heated cavity is studied numerically. By combining temporal integration, steady state solving and linear stability analysis of the full PDE equations, we have been able to locate and characterize a codimension-three degenerate Takens-Bogdanov point whose unfolding describes the dynamics of the system for a certain range of Rayleigh numbers and separation ratios near S=-1.Comment: 8 pages, 5 figure

Law and finance: empirical evidence from Germany, Spain, Portugal and Brazil

The global financial crisis of 2008 proved that many affected countries did not have effective insolvency laws at that moment. The increase of companies’ insolvencies made it clear that reforms needed to be urgently proposed to amend the inaccurate proceedings. However, not all of the commenced insolvency reforms ended up having the impact upon debtors and creditors that it was intended. The purpose of this paper is thus to prove whether said reforms had a meaningful effect in a group of selected countries upon creditors. I provide a general overview of the insolvency laws for Germany, Spain, Portugal, and Brazil and describe some insolvency reforms that have come into force there recently. The paper then proceeds to the empirical analysis of companies’ data, where descriptive but mostly inferential statistics are implemented, to examine whether investors changed their lending behaviour after the reforms’ commencement. The Chow test and the Difference-in-difference estimation combined with a matching approach are two techniques used to give an answer to this question. The results show that Brazil is the only country where the commencement of the insolvency refom had a true impact upon leverage. Because the Brazilian insolvency law of study is thought to be a creditor-friendly reform, at least in some aspects, we observe that these results support the perspective that stronger creditor rights cause a decrease of financial leverage, also called demand-side view. Stronger creditor rights imply a higher chance that the companies’ management will lose jobs and control in case of bankruptcy and thus the management feels reticent to rely on external financing

Sentido, verdad y afirmación en el pensamiento de F. Nietzsche.

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HEGEL, G. W. F.: El sistema de la eticidad

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