Corporate Income Taxation of Multinationals and Fiscal Equalization

This paper investigates the effect of fiscal equalization on the efficiency properties of corporate income tax rates chosen by symmetric countries in a Nash tax competition game under the taxation principles of Separate Accounting and Formula Apportionment. Fiscal equalization ensures efficiency if the marginal transfer just reflects the fiscal and pecuniary externalities of tax rates. In contrast to previous studies, tax base equalization (Representative Tax System) does not satisfy this condition, but combining tax revenue and private income equalization does, regardless of which taxation principle is implemented. Under Formula Apportionment, tax base equalization is superior to tax revenue equalization if the wage income externality is sufficiently large.separate accounting, formula apportionment, fiscal equalization

Corporate Income Taxation of Multinationals and Fiscal Equalization

This paper investigates the eect of scal equalization on the efficiency properties of corporate income tax rates chosen by symmetric countries in a Nash tax competition game under the taxation principles of Separate Accounting and Formula Apportionment. Fiscal equalization ensures efficiency if the marginal transfer just reects the scal and pecuniary externalities of tax rates. In contrast to previous studies, tax base equalization (Representative Tax System) does not satisfy this condition, but combining tax revenue and private income equalization does, regardless of which taxation principle is implemented. Under Formula Apportionment, tax base equalization is superior to tax revenue equalization if the wage income externality is suffciently large.Separate Accounting, Formula Apportionment, Fiscal Equalization

Approximations of the aggregated interference statistics for outage analysis in massive MTC

This paper presents several analytic closed-form approximations of the aggregated interference statistics within the framework of uplink massive machine-type-communications (mMTC), taking into account the random activity of the sensors. Given its discrete nature and the large number of devices involved, a continuous approximation based on the Gram–Charlier series expansion of a truncated Gaussian kernel is proposed. We use this approximation to derive an analytic closed-form expression for the outage probability, corresponding to the event of the signal-to-interference-and-noise ratio being below a detection threshold. This metric is useful since it can be used for evaluating the performance of mMTC systems. We analyze, as an illustrative application of the previous approximation, a scenario with several multi-antenna collector nodes, each equipped with a set of predefined spatial beams. We consider two setups, namely single- and multiple-resource, in reference to the number of resources that are allocated to each beam. A graph-based approach that minimizes the average outage probability, and that is based on the statistics approximation, is used as allocation strategy. Finally, we describe an access protocol where the resource identifiers are broadcast (distributed) through the beams. Numerical simulations prove the accuracy of the approximations and the benefits of the allocation strategy.Peer ReviewedPostprint (published version

Front motion in an A+B→CA+B\to C type reaction-diffusion process: Effects of an electric field

We study the effects of an external electric field on both the motion of the reaction zone and the spatial distribution of the reaction product, $C$, in an irreversible $A^- +B^+ \to C$ reaction-diffusion process. The electrolytes $A\equiv (A^+,A^-)$ and $B\equiv (B^+,B^-)$ are initially separated in space and the ion-dynamics is described by reaction-diffusion equations obeying local electroneutrality. Without an electric field, the reaction zone moves diffusively leaving behind a constant concentration of $C$-s. In the presence of an electric field which drives the reagents towards the reaction zone, we find that the reaction zone still moves diffusively but with a diffusion coefficient which slightly decreases with increasing field. The important electric field effect is that the concentration of $C$-s is no longer constant but increases linearly in the direction of the motion of the front. The case of an electric field of reversed polarity is also discussed and it is found that the motion of the front has a diffusive, as well as a drift component. The concentration of $C$-s decreases in the direction of the motion of the front, up to the complete extinction of the reaction. Possible applications of the above results to the understanding of the formation of Liesegang patterns in an electric field is briefly outlined.Comment: 13 pages, 13 figures, submitted to J. Chem. Phy

Energy-driven techniques for massive machine-type communications

In the last few years, a lot of effort has been put into the development of the fifth generation of cellular networks (5G). Given the vast heterogeneity of devices coexisting in these networks, new approaches have been sought to meet all requirements (e.g., data rate, coverage, delay, etc.). Within that framework, massive machine-type communications (mMTC) emerge as a promising candidate to enable many Internet of Things applications. mMTC define a type of systems where large sets of simple and battery-constrained devices transmit short data packets simultaneously. Unlike other 5G use cases, in mMTC, a low cost and power consumption are extensively pursued. Due to these specifications, typical humantype communications (HTC) solutions fail in providing a good service. In this dissertation, we focus on the design of energy-driven techniques for extending the lifetime of mMTC terminals. Both uplink (UL) and downlink (DL) stages are addressed, with special attention to the traffic models and spatial distribution of the devices. More specifically, we analyze a setup where groups of randomly deployed sensors send their (possibly correlated) observations to a collector node using different multiple access schemes. Depending on their activity, information might be transmitted either on a regular or sporadic basis. In that sense, we explore resource allocation, data compression, and device selection strategies to reduce the energy consumption in the UL. To further improve the system performance, we also study medium access control protocols and interference management techniques that take into account the large connectivity in these networks. On the contrary, in the DL, we concentrate on the support of wireless powered networks through different types of energy supply mechanisms, for which proper transmission schemes are derived. Additionally, for a better representation of current 5G deployments, the presence of HTC terminals is also included. Finally, to evaluate our proposals, we present several numerical simulations following standard guidelines. In line with that, we also compare our approaches with state-of-the-art solutions. Overall, results show that the power consumption in the UL can be reduced with still good performance and that the battery lifetimes can be improved thanks to the DL strategies.En els últims anys, s'han dedicat molts esforços al desenvolupament de la cinquena generació de telefonia mòbil (5G). Donada la gran heterogeneïtat de dispositius coexistint en aquestes xarxes, s'han buscat nous mètodes per satisfer tots els requisits (velocitat de dades, cobertura, retard, etc.). En aquest marc, les massive machine-type communications (mMTC) sorgeixen com a candidates prometedores per fer possible moltes aplicacions del Internet of Things. Les mMTC defineixen un tipus de sistemes en els quals grans conjunts de dispositius senzills i amb poca bateria, transmeten simultàniament paquets de dades curts. A diferència d'altres casos d'ús del 5G, en mMTC es persegueix un cost i un consum d'energia baixos. A causa d'aquestes especificacions, les solucions típiques de les human-type communications (HTC) no aconsegueixen proporcionar un bon servei. En aquesta tesi, ens centrem en el disseny de tècniques basades en l'energia per allargar la vida útil dels terminals mMTC. S'aborden tant les etapes del uplink (UL) com les del downlink (DL), amb especial atenció als models de trànsit i a la distribució espacial dels dispositius. Més concretament, analitzem un escenari en el qual grups de sensors desplegats aleatòriament, envien les seves observacions (possiblement correlades) a un node col·lector utilitzant diferents esquemes d'accés múltiple. Depenent de la seva activitat, la informació es pot transmetre de manera regular o esporàdica. En aquest sentit, explorem estratègies d'assignació de recursos, compressió de dades, i selecció de dispositius per reduir el consum d'energia en el UL. Per millorar encara més el rendiment del sistema, també estudiem protocols de control d'accés al medi i tècniques de gestió d'interferències que tinguin en compte la gran connectivitat d'aquestes xarxes. Per contra, en el DL, ens centrem en el suport de les wireless powered networks mitjançant diferents mecanismes de subministrament d'energia, per als quals es deriven esquemes de transmissió adequats. A més, per una millor representació dels desplegaments 5G actuals, també s'inclou la presència de terminals HTC. Finalment, per avaluar les nostres propostes, presentem diverses simulacions numèriques seguint pautes estandarditzades. En aquesta línia, també comparem els nostres enfocaments amb les solucions de l'estat de l'art. En general, els resultats mostren que el consum d'energia en el UL pot reduir-se amb un bon rendiment i que la durada de la bateria pot millorar-se gràcies a les estratègies del DL.En los últimos años, se han dedicado muchos esfuerzos al desarrollo de la quinta generación de telefonía móvil (5G). Dada la gran heterogeneidad de dispositivos coexistiendo en estas redes, se han buscado nuevos métodos para satisfacer todos los requisitos (velocidad de datos, cobertura, retardo, etc.). En este marco, las massive machine-type communications (mMTC) surgen como candidatas prometedoras para hacer posible muchas aplicaciones del Internet of Things. Las mMTC definen un tipo de sistemas en los cuales grandes conjuntos de dispositivos sencillos y con poca batería, transmiten simultáneamente paquetes de datos cortos. A diferencia de otros casos de uso del 5G, en mMTC se persigue un coste y un consumo de energía bajos. A causa de estas especificaciones, las soluciones típicas de las human-type communications (HTC) no consiguen proporcionar un buen servicio. En esta tesis, nos centramos en el diseño de técnicas basadas en la energía para alargar la vida ´útil de los terminales mMTC. Se abordan tanto las etapas del uplink (UL) como las del downlink (DL), con especial atención a los modelos de tráfico y a la distribución espacial de los dispositivos. Más concretamente, analizamos un escenario en el cual grupos de sensores desplegados aleatoriamente, envían sus observaciones (posiblemente correladas) a un nodo colector utilizando diferentes esquemas de acceso múltiple. Dependiendo de su actividad, la información se puede transmitir de manera regular o esporádica. En este sentido, exploramos estrategias de asignación de recursos, compresión de datos, y selección de dispositivos para reducir el consumo de energía en el UL. Para mejorar todavía más el rendimiento del sistema, también estudiamos protocolos de control de acceso al medio y técnicas de gestión de interferencias que tengan en cuenta la gran conectividad de estas redes. Por el contrario, en el DL, nos centramos en el soporte de las wireless powered networks mediante diferentes mecanismos de suministro de energía, para los cuales se derivan esquemas de transmisión adecuados. Además, para una mejor representación de los despliegues 5G actuales, también se incluye la presencia de terminales HTC. Finalmente, para evaluar nuestras propuestas, presentamos varias simulaciones numéricas siguiendo pautas estandarizadas. En esta línea, también comparamos nuestros enfoques con las soluciones del estado del arte. En general, los resultados muestran que el consumo de energía en el UL puede reducirse con un buen rendimiento y que la duración de la batería puede mejorarse gracias a las estrategias del DLPostprint (published version

Lithogenesis of a phosphatized tephra marker horizon in the Eocene Messel maar lake

The bituminous black pelite of the Messel UNESCO world heritage site is an exceptional palaeobiological archive from the Middle Eocene greenhouse climate. The pronounced homogeneity of the annually laminated pelite through a time interval of 640 kyr complicates the relative stratigraphic classification of fossil remains and is, thus, largely dependent on particular marker horizons within the uniform sedimentary column. We analyzed the most prominent marker horizon M using petrographic microscopy, X-ray powder diffraction, and electron probe microanalyses to identify and characterize its structure and phosphate-dominated mineralogy. Based on our analytical data, we suggest that this phosphatic marker horizon resulted from the exceptional combination of external tephra enclosed in bacteria and algae-rich layers, producing a coupled phosphorus and cation diffusion during diagenesis. Mantienneite (KMg2Al2Ti(PO4)4(OH)3 • 15H2O) is documented for the first time in the Messel fossil deposit. The diagenetic succession of messelite, montgomeryite, and mantienneite precipitation reflects the internal heterogeneities in primary mineral composition of an ash layer. Kerogen maturation and hydrocarbon migration produced acidic, reducing pore fluids with high P concentration, which enhanced the mobility of Al and Ti. The mantienneite-forming reaction marks the change from a regime of reducing to oxidizing conditions. With the deposition and diagenesis of the marker horizon M, a singular event is preserved in a sedimentary sequence otherwise regarded as largely uniform over a time span of about 640 kyr

EMF-Aware Power Control for Massive MIMO: Cell-Free versus Cellular Networks

The impressive growth of wireless data networks has recently led to increased attention to the issue of electromagnetic pollution. Specific absorption rates and incident power densities have become popular indicators for measuring electromagnetic field (EMF) exposure. This paper tackles the problem of power control in user-centric cell-free massive multiple-input-multiple-output (CF-mMIMO) systems under EMF constraints. Specifically, the power allocation maximizing the minimum data rate across users is derived for both the uplink and the downlink under EMF constraints. The developed solution is also applied to a cellular mMIMO system and compared to other benchmark strategies. Simulation results prove that EMF safety restrictions can be easily met without jeopardizing the minimum data rate, that the CF-mMIMO outperforms the multi-cell massive MIMO deployment, and that the proposed power control strategy greatly improves the system fairness.Comment: This work has been submitted to IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessibl

Corporate Income Taxation of Multinationals and Fiscal Equalization

This paper investigates the e ect of scal equalization on the efficiency properties of corporate income tax rates chosen by symmetric countries in a Nash tax competition game under the taxation principles of Separate Accounting and Formula Apportionment. Fiscal equalization ensures efficiency if the marginal transfer just reects the scal and pecuniary externalities of tax rates. In contrast to previous studies, tax base equalization (Representative Tax System) does not satisfy this condition, but combining tax revenue and private income equalization does, regardless of which taxation principle is implemented. Under Formula Apportionment, tax base equalization is superior to tax revenue equalization if the wage income externality is suffciently large

Lithogenesis of a phosphatized tephra marker horizon in the Eocene Messel maar lake

The bituminous black pelite of the Messel UNESCO world heritage site is an exceptional palaeobiological archive from the Middle Eocene greenhouse climate. The pronounced homogeneity of the annually laminated pelite through a time interval of 640 kyr complicates the relative stratigraphic classification of fossil remains and is, thus, largely dependent on particular marker horizons within the uniform sedimentary column. We analyzed the most prominent marker horizon M using petrographic microscopy, X-ray powder diffraction, and electron probe microanalyses to identify and characterize its structure and phosphate-dominated mineralogy. Based on our analytical data, we suggest that this phosphatic marker horizon resulted from the exceptional combination of external tephra enclosed in bacteria and algae-rich layers, producing a coupled phosphorus and cation diffusion during diagenesis. Mantienneite (KMg2Al2Ti(PO4)4(OH)3 • 15H2O) is documented for the first time in the Messel fossil deposit. The diagenetic succession of messelite, montgomeryite, and mantienneite precipitation reflects the internal heterogeneities in primary mineral composition of an ash layer. Kerogen maturation and hydrocarbon migration produced acidic, reducing pore fluids with high P concentration, which enhanced the mobility of Al and Ti. The mantienneite-forming reaction marks the change from a regime of reducing to oxidizing conditions. With the deposition and diagenesis of the marker horizon M, a singular event is preserved in a sedimentary sequence otherwise regarded as largely uniform over a time span of about 640 kyr