42 research outputs found
The Branch-and-Bound Algorithm in Optimizing Mathematical Programming Models to Achieve Power Grid Observability
No full textPhasor Measurement Units (PMUs) are the backbone of smart grids that are able to measure power system observability in real-time. The deployment of synchronized sensors in power networks opens up the advantage of real-time monitoring of the network state. An optimal number of PMUs must be installed to ensure system observability. For that reason, an objective function is minimized, reflecting the cost of PMU installation around the power grid. As a result, a minimization model is declared where the objective function is defined over an adequate number of constraints on a binary decision variable domain. To achieve maximum network observability, there is a need to find the best number of PMUs and put them in appropriate locations around the power grid. Hence, maximization models are declared in a decision-making way to obtain optimality satisfying a guaranteed stopping and optimality criteria. The best performance metrics are achieved using binary integer, semi-definite, and binary polynomial models to encounter the optimal number of PMUs with suitable PMU positioning sites. All optimization models are implemented with powerful optimization solvers in MATLAB to obtain the global solution point
The socialist frenzy of two decades
No full textTitle: ‘O σoσιαλιστικός ὀργασμός δύo δεκαετιῶν (The socialist frenzy of two decades) Original published: In installments in the newspaper Tαχυδρόμoς (Postman) in 1931 Language: GreekThe excerpts used are from the latest edition entitled ‘H πρώτη καριέρα τoῦ έλληνκοῦ προλετριάτου (The first career of the Greek proletariat) with an introduction by Angelos Elefantis (’Aθήνα:’ Iολκός 1975), p. 69–72. About the author Abraham Benaroya [1887, Vidin (present-day north-west Bulgaria) – 1979, Holon (I..
Mathematical Models for the Single-Channel and Multi-Channel PMU Allocation Problem and Their Solution Algorithms
No full textPhasor measurement units (PMUs) are deployed at power grid nodes around the transmission grid, determining precise power system monitoring conditions. In real life, it is not realistic to place a PMU at every power grid node; thus, the lowest PMU number is optimally selected for the full observation of the entire network. In this study, the PMU placement model is reconsidered, taking into account single- and multi-capacity placement models rather than the well-studied PMU placement model with an unrestricted number of channels. A restricted number of channels per monitoring device is used, instead of supposing that a PMU is able to observe all incident buses through the transmission connectivity lines. The optimization models are declared closely to the power dominating set and minimum edge cover problem in graph theory. These discrete optimization problems are directly related with the minimum set covering problem. Initially, the allocation model is declared as a constrained mixed-integer linear program implemented by mathematical and stochastic algorithms. Then, the 0/1 integer linear problem is reformulated into a non-convex constraint program to find optimality. The mathematical models are solved either in binary form or in the continuous domain using specialized optimization libraries, and are all implemented in YALMIP software in conjunction with MATLAB. Mixed-integer linear solvers, nonlinear programming solvers, and heuristic algorithms are utilized in the aforementioned software packages to locate the global solution for each instance solved in this application, which considers the transformation of the existing power grids to smart grids
Optimisation of Complex Geometry High-Rise Buildings based on Wind Load Analysis
No full textWind analysis for the structure of buildings is a challenging process. The increasing strength and frequency of wind events due to climate change only add higher demands. In addition, high-rise buildings are growing in number and include many of unconventional shape. Current methods used in practice for calculating structural wind response either do not account for these geometries, such as the Eurocode or are prohibitively time-consuming and expensive, such as physical wind tunnel tests and complex Computational Fluid Dynamics simulations. As such, wind loads are usually only considered towards the end of design. This paper presents the development of a computational method to analyse the effect of wind on the structural behaviour of a 3D building model and optimise the external geometry to reduce those effects at an early design phase. It combines Computational Fluid Dynamics (CFD), Finite Element Analysis (FEA), and an Optimisation algorithm. This allows it to be used in an early design stage for performance-based design exploration in complement to the more traditional late-stage methods outlined above. The method was implemented into a rapid and easy to use computational tool by combining existing plugins in Grasshopper into a single script that can be used in practice on complex shaped parametric high-rise building models. After developing the method and testing the timeliness and precision of the CFD, and FEA portions on case study buildings, the tool was able to output an optimal geometry as well as a database of improved geometric options with their corresponding performance for the wind loading allowingfor performance-based decision-making in the early design phase.Design InformaticsStructural Design & Mechanic
The Rise of America\u27s Two National Pastimes: Baseball and the Law
Get PDFMark McGwire\u27s seventieth home run ball sold at auction in January of this year for $3,005,000. In late 1998, Baltimore Orioles owner Peter Angelos sued a former Orioles manager and his daughter in the circuit court of Cook County, Illinois. Angelos alleged that the original lineup card from the 1995 game when Cal Ripken, Jr., broke Lou Gehrig\u27s consecutive game record belongs to the Orioles, not to the former manager and certainly not to his daughter. There may be no crying in baseball, but there is money. And wherever earthly treasure gathers two or more, a legal system arises. From this confluence of forces is born Legal Bases: Baseball and the Law, a recent addition to that burgeoning genre of nonfiction works about the business and law of baseball. Legal Bases intends to inform a lay audience about basic legal concepts that have shaped baseball as well as other aspects of American law and culture: antitrust law and monopolies, collective bargaining, labor arbitration, enforcement of private contractual rights, and an overview of the civil justice system. In the process, author Roger I. Abrams introduces Legal Bases as a teaching tool that uses baseball as the backdrop to discuss the role in American society of law, legal institutions, and private ordering in the development of a significant American business enterprise (p. 3)
Multivariate Interactive Visualization of Data in Generative Design
No full textSimAUD 2016 conference paper with high resolution images and presentation slidesIn this paper we describe our work on providing support for design decision making in generative design systems producing large quantities of simulation data. The work is motivated by the continuing challenge of making sense of large design and simulation result datasets. Our approach is to provide methods and tools for multivariate interactive data visualization of the generated designs and simulation results. These enable designers to focus not only on high-performing results but also to examine suboptimal designs’ attributes and outcomes so as to discover relationships giving greater insight to design performance and facilitating guidance of further design generation. We illustrate this with an example exploring building massing and envelope design (fenestration arrangement and external shading) with simulations of daylighting and heat gain. We conclude that the visualization techniques investigated are potentially useful in helping designers to better comprehend the inter-relationships between variable parameters, constraints and outcomes, with consequent benefits in finding good design outcomes as well as in verifying that simulation results are reliable and understanding characteristics of the fitness landscape.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/117408/1/Figure1.jpgDescription of Figure1.jpg : Figure 1. Examples of different design solution images
Cult-song and festival revival in Hellenistic Athens
No full textThis embraces two central goals. In the first case, it seeks to demonstrate that the revival of civic religious festivals, an understudied element of ancient life, was a recognized category of religious activity during the Hellenistic period, similar to and influenced by the other changes in festival status that were common at the time. The second goal builds upon the first to examine the performance culture of these revived festivals and focuses especially on the music performed at the Pythaïs festival that the Athenians revived in 138/7 BCE and periodically celebrated at Delphi. Athenian performance at the Pythaïs is uniquely well-documented, as two hymns to Apollo that formed part of the celebration of 128/7 BCE were inscribed along with their musical notation on the Athenian Treasury at Delphi, the only such example to have survived from the Greek world. This dissertation offers a reading of these hymns and their accompanying music in the context of their revived festival performance as calculated engagements with the city’s legendary and historical pasts that sought to position the city of Athens as the cultural leader of the Greek world in the shadow of the newly ascendant Roman empire.The first chapter assesses the language found in accounts and documents related to festival revival and delineates the semantic field within which festival revival took place, dominated by diplomatic and construction activity. The second chapter concerns the discourse related to festival revival that existed at Athens during the Archaic and Classical periods. This analysis settles initially on the origin myths of the four great Panhellenic festivals, before turning attention to the revived Athenian Delia festival on Delos in the late-fifth century BCE and the choral performances that it hosted and that serve as an important model for analysis of the Delphic Hymns. Finally, this chapter considers the dramatization of festival revival in Aristophanes’ Acharnians and Peace to show that festival revival was a recognized feature of Athenian religious culture throughout the Classical period.
With some context established, the third chapter turns to the dossier of documents related to the celebrations of the Pythaïs in 138/7 and 128/7 BCE and focuses especially on how this dossier can inform an understanding of the Delphic Hymns. These documents demonstrate that the Athenians presented themselves in 128/7 as an embodiment of the democratic city of the Classical period and a preserver of its civic and military prowess and ideology. The city was joined in its self-presentation by the Athenian Dionysiac Artists, the musicians who composed and performed the two hymns for the festival. These hymns with their complementary musical notation — one instrumental and one vocal — served as evidence of Athens’ long history with Delphi, but were also a potent advertisement of Athenian musical, and hence cultural, expertise. The Hymns honored both the city of Athens and its musical elite and their acknowledgement of the revived performance setting of the Pythaïs endowed the compositions with a historical depth that masterfully exploited their position on the Athenian Treasury at Delphi.Ph.D.Includes bibliographical reference
Prevalencia del maltrato intrafamiliar y factores asociados en estudiantes del cantón Méndez, 2009
Get PDFEs un estudio transversal realizado en los estudiantes de los colegios secundarios del cantón Méndez, que aceptaron participar con la autorización de sus padres, y a quienes se aplicó una encuesta elaborada por la autora, previamente validada. Para la tabulación y análisis se aplicó el programa Epi Info versión 3.3.2. OR. IC 95%, los resultados serán difundidos en los colegios a través de sus autoridades, con charlas educativas, tanto al adolescente como a sus representantes y a la población en general; a través de la radio y boletines de prensa. Resultados: la prevalencia del maltrato fue de 67,7%, y afectó más al sexo femenino 77,6%, a la etnia Shuar 71,8%, y las edades de 10 a 13 años con un 69,9%. El factor asociado de mayor relevancia fue violencia en el hogar (IC 5.00- 11.88 P= 0,00). Conclusiones: la prevalencia del maltrato y sus factores asociados fue alta, en los estudiantes de los colegios secundarios del cantón Méndez. AUABSTRACT:
Abuse, within the family framework is frequently and our country is not free of this, which has been demonstrated by high rates 75% (UNICEF), for this reason it’s imperative to make studies to know the reality of our peoples and raise timely responses.
Objective: To determine the prevalence of abuse in the family environment and associated factors among students in secondary schools in the cantón Méndez of Morona Santiago province´s, enrolled in school´s year 2008 -2009.
Methodology: It is a cross-sectional study among students in secondary schools in the cantón Mendez, who agreed to participate with the permission of their parents, and were submitted to a survey conducted by the author, previously validated. For tabulation and analysis was applied Epi Info version 3.3.2. OR. 95%, the results will be disseminated in schools through their authorities, educational talks, both the adolescent and their representatives and the general public, through radio and press releases.
Results: The prevalence of abuse was 67.7%, affecting more females 77.6% to 71.8% Shuar ethnic group, and the ages of 10-13 years with 69.9%. The most important factor was associated with domestic violence (CI 5.00-11.88 P = 0.00).
Conclusions: The prevalence of abuse and associated factors was high among students in secondary schools in the canton Mendez.
Keywords: Abuse, associated factors, adolescents.Magíster en Salud PúblicaCuenc
