Scheduling for Optimal Rate Allocation in Ad Hoc Networks With Heterogeneous Delay Constraints

This paper studies the problem of scheduling in single-hop wireless networks with real-time traffic, where every packet arrival has an associated deadline and a minimum fraction of packets must be transmitted before the end of the deadline. Using optimization and stochastic network theory we propose a framework to model the quality of service (QoS) requirements under delay constraints. The model allows for fairly general arrival models with heterogeneous constraints. The framework results in an optimal scheduling algorithm which fairly allocates data rates to all flows while meeting long-term delay demands. We also prove that under a simplified scenario our solution translates into a greedy strategy that makes optimal decisions with low complexity

Anther culture in the tomato (Lycopersicon esculentum Mill) callus and plantlet production studies

In vitro anther culture is a promising tool for the obtention of haploid or dihaploid plants. In some crops, it has been useful for plant breeding purposes, but not in the tomato. For this study we chose the anther-to-plantlet pathway which apparently is the best way of obtaining the desired plants;There are different approaches for the obtention of calluses and the possibility of improving the response is high when results from other species are taken into account. The objective of the work reported in this dissertation was to evaluate a series of factors influencing the production and regeneration of calluses. With this we wished to define a protocol that could be used with a wide range of genotypes with good results;For the development of the protocol we evaluated factors such as media, media components, growth regulators, genotypes, anther development stage, temperature, pretreatments, and dark-light pretreatments. Results indicated that there are suitable media, as in the case of DBM[subscript]1, that can be improved further with the use of filtered thiamine and pyridoxine and the selection and proper concentration of the agar type. The use of dark treatment for incubation increased not only the number but the diameter of calluses. The most striking effect on number of callus was related to the development of the anther. When plated at the beginning of prophase I the more the anthers produced calluses. On the other hand it was possible to induce callus, although in lower numbers, at any stage of anther development including the first mitosis;Genotypic differences were very stable across the different treatments evaluated, however, growth regulators, vitamins, and agar type among others may increase the response in low callus yielding cultivars;Regeneration results were low but promising. The medium MS developed by Murashige and Skoog in 1962 plus zeatin and IAA induced formation of plantlets probably originating from the sporogenous tissue. No ploidy level was confirmed

The Political Economy of Exchange Rate Policy in Colombia

This paper looks into the political economy forces that helped shape exchange rate policy in Colombia since the early 1960s. As witnessed by the remarkable longevity of the managed crawl, Colombian exchange rate policies since 1967 did not take the form of major regime changes. Policy shifts came about through variations in the rate of crawl, varying degrees of administrative restrictions on capital flows and, on occasions, ad-hoc measures to generate multiple exchange rates.

POBREZA Y DEUDA EXTERNA

El Ecuador conoce el endeudamiento desde lejanas épocas. En efecto la primera deuda fue contraída para afrontar los gastos de la guerra de la independencia. Sin embargo esa vieja deuda nunca fue tan pesada ni intolerable como ha llegado a ser la actual

Deformed Jarzynski Equality

The well-known Jarzynski equality, often written in the form $e^{-\beta\Delta F}=\langle e^{-\beta W}\rangle$, provides a non-equilibrium means to measure the free energy difference $\Delta F$ of a system at the same inverse temperature $\beta$ based on an ensemble average of non-equilibrium work $W$. The accuracy of Jarzynski's measurement scheme was known to be determined by the variance of exponential work, denoted as ${\rm var}\left(e^{-\beta W}\right)$. However, it was recently found that ${\rm var}\left(e^{-\beta W}\right)$ can systematically diverge in both classical and quantum cases. Such divergence will necessarily pose a challenge in the applications of Jarzynski equality because it may dramatically reduce the efficiency in determining $\Delta F$. In this work, we present a deformed Jarzynski equality for both classical and quantum non-equilibrium statistics, in efforts to reuse experimental data that already suffers from a diverging ${\rm var}\left(e^{-\beta W}\right)$. The main feature of our deformed Jarzynski equality is that it connects free energies at different temperatures and it may still work efficiently subject to a diverging ${\rm var}\left(e^{-\beta W}\right)$. The conditions for applying our deformed Jarzynski equality may be met in experimental and computational situations. If so, then there is no need to redesign experimental or simulation methods. Furthermore, using the deformed Jarzynski equality, we exemplify the distinct behaviors of classical and quantum work fluctuations for the case of a time-dependent driven harmonic oscillator dynamics and provide insights into the essential performance differences between classical and quantum Jarzynski equalities.Comment: 24 pages, 1 figure, accepted version to appear in Entropy (Special Issue on "Quantum Thermodynamics"

Sustainability in urban transport plans. Case study: Monorail in a hillside area in Medellín

[EN] One of the most important concepts today is the incorporation of sustainability in urban transport plans. This paper presents the importance that sustainable urban transport plans must have on mobility policy in cities. It also shows the factors that make a transportation mode like urban railway be sustainable. Finally, the Monorail project in the Metropolitan Green Belt (Medellín-Colombia) is presented, showing its implication on the mobility in this low-income region and its integration with urban and regional plans.Pineda Jaramillo, J. (2016). Sustainability in urban transport plans. Case study: Monorail in a hillside area in Medellín. En XII Congreso de ingeniería del transporte. 7, 8 y 9 de Junio, Valencia (España). Editorial Universitat Politècnica de València. 1728-1734. https://doi.org/10.4995/CIT2016.2016.3183OCS1728173