An Optimal and Distributed Method for Voltage Regulation in Power Distribution Systems

This paper addresses the problem of voltage regulation in power distribution networks with deep-penetration of distributed energy resources, e.g., renewable-based generation, and storage-capable loads such as plug-in hybrid electric vehicles. We cast the problem as an optimization program, where the objective is to minimize the losses in the network subject to constraints on bus voltage magnitudes, limits on active and reactive power injections, transmission line thermal limits and losses. We provide sufficient conditions under which the optimization problem can be solved via its convex relaxation. Using data from existing networks, we show that these sufficient conditions are expected to be satisfied by most networks. We also provide an efficient distributed algorithm to solve the problem. The algorithm adheres to a communication topology described by a graph that is the same as the graph that describes the electrical network topology. We illustrate the operation of the algorithm, including its robustness against communication link failures, through several case studies involving 5-, 34-, and 123-bus power distribution systems.Comment: To Appear in IEEE Transaction on Power System

Models from code or code as a model?

Many model-driven engineering workflows take the existing code of a system as an input. Some of these include validation and verification, software modernisation or knowledge extraction. Current approaches take the code and produce a standalone model, instead of treating the code itself as a model and navigating through it on demand. For very large codebases this can be quite expensive to produce, and the resulting model can be too large to suit the simplest monolithic file-based stores. In this work we propose reusing a model that is already incrementally built for us and supports fast lookups: the internal indices maintained by our integrated development environments for code analysis and refactoring. In particular, we show an Epsilon driver that exposes the Eclipse JDT indices of one or more Java projects as a model, and compare its performance and usability against MoDisco for validating Java code with regards to a partial UML model

Using EcoYieldSAFE to compare soil carbon dynamics under future climate in two contrasting agroforestry systems

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Infratentorial hygroma secondary to decompressive craniectomy after cerebellar infarction

We present a case of expansive CSF collection in the cerebellar convexity. The patient was a 74 years old lady who one month before had suffered a cerebellar infarct complicated with acute hydrocephalus. She had good evolution after decompressive craniectomy without shunting. Fifteen days after surgery, the patient started with new positional vertigo, nausea and vomiting and a wound CSF fistula that needed ventriculoperitoneal shunt (medium pressure) because conservative treatment failed. After shunting, the fistula closed, but the patient symptoms worsened. The MRI showed normal ventricular size with a cerebellar hygroma, extending to the posterior interhemispheric fissure. The collection had no blood signal and expanded during observation. A catheter was implanted in the collection and connected to the shunt. The patient became asymptomatic after surgery, and the hygromas had disappeared in control CT at one month. This case shows an infrequent problem of CSF circulation at posterior fossa that resulted in vertigo of central origin. A higroma-ventricle-peritoneal shunt solved the symptoms of the patient

Use of camera trapping in determining Iberian lynx population parameters: The use area and its limitations

Below are the results of the survey of the Iberian lynx obtained with camera-trapping between 2000 and 2007 in Sierra Morena. Two very important aspects of camera-trapping concerning its efficiency are also analyzed. The first is the evolution along years according to the camera-trapping type used of two efficiency indicators. The results obtained demonstrate that the most efficient lure is rabbit, though it is the less proven (92 trap-nights), followed by camera-trapping in the most frequent marking places (latrines). And, we propose as a novel the concept of use area as a spatial reference unit for the camera-trapping monitoring of non radio-marked animals is proposed, and its validity discussed

The Nearby Optical Galaxy Sample: The Local Galaxy Luminosity Function

In this paper we derive the galaxy luminosity function from the Nearby Optical Galaxy (NOG) sample, which is a nearly complete, magnitude-limited (B<14 mag), all-sky sample of nearby optical galaxies (~6400 galaxies with cz<5500 km/s). For this local sample, we use galaxy distance estimates based on different peculiar velocity models. Therefore, the derivation of the luminosity function is carried out using the locations of field and grouped galaxies in real distance space. The local field galaxy luminosity function in the B system is well described by a Schechter function. The exact values of the Schechter parameters slightly depend on the adopted peculiar velocity field models. The shape of the luminosity function of spiral galaxies does not differ significantly from that of E-S0 galaxies. On the other hand, the late-type spirals and irregulars have a very steeply rising luminosity function towards the faint end, whereas the ellipticals appreciably decrease in number towards low luminosities. The presence of galaxy systems in the NOG sample does not affect significantly the field galaxy luminosity function, since environmental effects on the total luminosity function appear to be marginal.Comment: 35 pages including 7 figures and 4 tables. Accepted for publication in Ap

Surgery guided by 5-aminolevulinic fluorescence in glioblastoma: volumetric analysis of extent of resection in singlecenter experience

We analyzed the efficacy and applicability of surgery guided by 5-aminolevulinic acid (ALA) fluorescence in consecutive patients with glioblastoma multiforme (GBM). Thirty-six patients with GBM were operated on using ALA fluorescence. Resections were performed using the fluorescent light to assess the right plane of dissection. In each case, biopsies with different fluorescent quality were taken from the tumor center, from the edges, and from the surrounding tissue. These samples were analyzed separately with hematoxylin-eosin examination and immunostaining against Ki67. Tumor volume was quantified with pre- and postoperative volumetric magnetic resonance imaging. Strong fluorescence identified solid tumor with 100% positive predictive value. Invaded tissue beyond the solid tumor mass was identified by vague fluorescence with 97% positive predictive value and 66% negative predictive value, measured against hematoxylin-eosin examination. All the contrast-enhancing volume was resected in 83.3% of the patients, all patients had resection over 98% of the volume and mean volume resected was 99.8%. One month after surgery there was no mortality, and new or increased neurological morbidity was 8.2%. The fluorescence induced by 5-aminolevulinic can help to achieve near total resection of enhancing tumor volume in most surgical cases of GBM. It is possible during surgery to obtain separate samples of the infiltrating cells from the tumor borde

MONDO : Scalable modelling and model management on the Cloud

Achieving scalability in modelling and MDE involves being able to construct large models and domain-specific languages in a systematic manner, enabling teams of modellers to construct and refine large models in collaboration, advancing the state of the art in model querying and transformations tools so that they can cope with large models (of the scale of millions of model elements), and providing an infrastructure for efficient storage, indexing and retrieval of large models. This paper outlines how MONDO, a collaborative EC-funded project, has contributed to tackling some of these scalability-related challenges