Unit commitment with valve-point loading effect

Valve-point loading affects the input-output characteristics of generating units, bringing the fuel costs nonlinear and nonsmooth. This has been considered in the solution of load dispatch problems, but not in the planning phase of unit commitment. This paper presents a mathematical optimization model for the thermal unit commitment problem considering valve-point loading. The formulation is based on a careful linearization of the fuel cost function, which is modeled with great detail on power regions being used in the current solution, and roughly on other regions. A set of benchmark instances for this problem is used for analyzing the method, with recourse to a general-purpose mixed-integer optimization solver

The Cluster Abundance in Flat and Open Cosmologies

We use the galaxy cluster X-ray temperature distribution function to constrain the amplitude of the power spectrum of density inhomogeneities on the scale corresponding to clusters. We carry out the analysis for critical density universes, for low density universes with a cosmological constant included to restore spatial flatness and for genuinely open universes. That clusters with the same present temperature but different formation times have different virial masses is included. We model cluster mergers using two completely different approaches, and show that the final results from each are extremely similar. We give careful consideration to the uncertainties involved, carrying out a Monte Carlo analysis to determine the cumulative errors. For critical density our result agrees with previous papers, but we believe the result carries a larger uncertainty. For low density universes, either flat or open, the required amplitude of the power spectrum increases as the density is decreased. If all the dark matter is taken to be cold, then the cluster abundance constraint remains compatible with both galaxy correlation data and the {\it COBE} measurement of microwave background anisotropies for any reasonable density.Comment: Uuencoded package containing LaTeX file (uses mn.sty) plus 7 postscript figures incorporated using epsf. Total length 10 pages. Final version, to appear MNRAS. COBE comparison changed to 4yr data. No change to results or conclusion

Online legal platforms – the beginning of the 4.0 law practice?

The 4.0 revolution has reached the legal services industry. New online platforms are emerging to connect clients and lawyers, while also providing new and innovative legal services. Nonetheless, several questions arise regarding these new businesses: How do they fare under the Portuguese regulatory framework? Is there a need for legislative reform? And how are Bar Associations dealing with this new reality? In order to answer these questions, we analyze the characteristics of online legal platforms and their compliance with the statutes of the Portuguese Bar Association and National Law. Secondly, we examine the prohibition by the Portuguese Bar Association of online intermediation platforms, taking into consideration the ECJ’s case law related to professional orders and the EU’s competition law. Thirdly, we study the national legal framework of legal services in light of OECD’s Competition Assessment Review of Portugal. Lastly, we present the recent project by the Portuguese Competition Authority and note its similarities with the ECJ’s case law

The inefficiencies of car utilization in urban areas - characterization of utopic optimal carsharing scenario, enablers and barriers that lead to different future transports mix and the pivotal role of technology enhancements

Urban mobility is under going a very big transformation. Appification is the phenomenon enabling a rapid change and the rise of new players relying heavily on technology to reach end users. The benefits are of various kinds and have real implication son environment as well as on socioeconomic conditions of those who live in urban areas. The future of urban mobility ecosystem is not yet completely defined, although it will probably be green erandsmarter

Kaliningrad and the Lithuanian “geopolitical code"

The paper analyses the evolving role of Kaliningrad in shaping Lithuania‟s security perceptions vis-à-vis Russia. Applying the framework of the “geopolitical code” designed by Flint, the authors question whether the exclave-enclave nexus in the Kaliningrad region ‒ after the European Union (EU) and the Atlantic Alliance (NATO) enlargements ‒ has been a relevant change in context that has affected Vilnius' security perception of Moscow in its “geopolitical code”. The cooperative posture of Vilnius initialled in 1991 ‒ and later reinforced through the EU programmes ‒ tended to be based on achieving the country and EU‟s own stability and development, in a regional perspective, with no strategy to spill over on global relations with Moscow. Vilnius' understanding of Russian policies in Georgia and, mainly Ukraine, represented a change in context from 2008 onwards that brought a focus on military dimensions concerning the Oblast. This change was convergent with the same tendency in NATO. Membership in the EU and NATO has reinforced Lithuanian perceptions of Kaliningrad as a potential ally or enemy. At the bottom line, Vilnius‟ key decisions towards militarization in detriment of cooperation result from a continued negative security perception of Russia. Although cooperative engagement exists, it has not been able to become a feature of the relation due to the rationale of this cooperation. Kaliningrad influenced the “geopolitical code” of Lithuania concerning Russia but it did not play a decisive role in changing Vilnius' calculations on how to engage with Moscow.(undefined

Cold dark matter models with high baryon content

Recent results have suggested that the density of baryons in the Universe, OmegaB, is much more uncertain than previously thought, and may be significantly higher. We demonstrate that a higher OmegaB increases the viability of critical-density cold dark matter (CDM) models. High baryon fraction offers the twin benefits of boosting the first peak in the microwave anisotropy power spectrum and of suppressing short-scale power in the matter power spectrum. These enable viable CDM models to have a larger Hubble constant than otherwise possible. We carry out a general exploration of high OmegaB CDM models, varying the Hubble constant h and the spectral index n. We confront a variety of observational constraints and discuss specific predictions. Although some observational evidence may favour baryon fractions as high as 20 per cent, we find that values around 10 to 15 per cent provide a reasonable fit to a wide range of data. We suggest that models with OmegaB in this range, with h about 0.5 and n about 0.8, are currently the best critical-density CDM models.Comment: 14 pages, LaTeX, with 9 included figures, to appear in MNRAS. Revised version includes updated references, some changes to section 4. Conclusions unchange