710 research outputs found
Symbolic Analysis of Large-Scale Networks
A new approach to the problem of symbolic circuit analysis of large-scale circuits is presented in this report. The methodology has been implemented in a computer program called SCAPP (Symbolic Circuit Analysis Program with Partitioning). The method solves the problem by utilizing a hierarchical network approach and the sequence of expressions concept rather than a topological approach and the single expression idea which have dominated symbolic analysis in the past. The method employs further modifications to the modified nodal analysis (MNA) technique by allowing ideal opamps in the matrix formulation process and introducing the reduced modified analysis matrix (RMNA). The analysis algorithm is most efficient when network partitioning is used. A node-tearing binary partitioning algorithm based on the concepts of loop index and tearing index is also presented. The partitioning technique is very suitable for the hierarchical network analysis approach
A Study of a Semi-Direct Method for Computer Analysis of Large-Scale Circuits
In this thesis a study of a Semi-Direct method for the solution of large scale circuits is presented. The method combines features from the Newton- Raphson method and the Gauss-Seidel method. These two methods are both illustrated. The Semi-Direct method is presented both theoretically and empirically using three programs developed for this purpose. The Semi-Direct method and the Newton-Raphson method are compared. The comparison includes speed (number of iterations and execution time) and storage requirements. The Semi-Direct method definitely has storage advantages over the Newton-Raphson method at all circuit levels of 2 or more nodes. If some set conditions are met in the circuit, the Semi-Direct method will require less CPU time to reach the solution than the Newton-Raphson metho
The Classical Limit of Quantum Mechanics and the Fejer Sum of the Fourier Series Expansion of a Classical Quantity
In quantum mechanics, the expectation value of a quantity on a quantum state,
provided that the state itself gives in the classical limit a motion of a
particle in a definite path, in classical limit goes over to Fourier series
form of the classical quantity. In contrast to this widely accepted point of
view, a rigorous calculation shows that the expectation value on such a state
in classical limit exactly gives the Fej\'{e}r's arithmetic mean of the partial
sums of the Fourier series
Making Free Trade Fair
Philosophers have done very little work on what makes trade fair. Perhaps the most extensive discussion is Malgorzata Kurjanska and Mathias Risseâs article, âFairness in Trade II: export subsidies and the fair trade movement.â2 In their article, Kurjanska and Risse consider the case for trade subsidies and the Fair Trade movement. They suggest that it is not permissible for developed countries to give their producers subsidies because doing so does not strike an appropriate balance between meeting the needs of the global poor and protecting domestic workers (Kurjanska and Risse, 2008: 34). Kurjanska and Risse also argue that the case for Fair Trade hinges, primarily, on whether or not it is part of the best development strategy for poor countries. They do not think Fair Trade is part of the best development strategy and, so, they believe purchasing Fair Trade certified goods is only acceptable because doing so does not constitute a large share of the market in traded goods. This chapter argues that the case against subsidies and Fair Trade Kurjanska and Risse present is much weaker than they make out. To the contrary, it argues that giving some subsidies and purchasing some Fair Trade certified goods may even be necessary to make trade fair. Section 11.2 starts by saying a few words about the normative framework Kurjanska and Risse adopt
Climatological variations of total alkalinity and total dissolved inorganic carbon in the Mediterranean Sea surface waters
Abstract. A compilation of data from several cruises between 1998 and 2013 was used to derive polynomial fits that estimate total alkalinity (AT) and total dissolved inorganic carbon (CT) from measurements of salinity and temperature in the Mediterranean Sea surface waters. The optimal equations were chosen based on the 10-fold cross-validation results and revealed that second- and third-order polynomials fit the AT and CT data respectively. The AT surface fit yielded a root mean square error (RMSE) of ± 10.6 ÎŒmol kgâ1, and salinity and temperature contribute to 96 % of the variability. Furthermore, we present the first annual mean CT parameterization for the Mediterranean Sea surface waters with a RMSE of ± 14.3 ÎŒmol kgâ1. Excluding the marginal seas of the Adriatic and the Aegean, these equations can be used to estimate AT and CT in case of the lack of measurements. The identified empirical equations were applied on the 0.25° climatologies of temperature and salinity, available from the World Ocean Atlas 2013. The 7-year averages (2005â2012) showed that AT and CT have similar patterns with an increasing eastward gradient. The variability is influenced by the inflow of cold Atlantic waters through the Strait of Gibraltar and by the oligotrophic and thermohaline gradient that characterize the Mediterranean Sea. The summerâwinter seasonality was also mapped and showed different patterns for AT and CT. During the winter, the AT and CT concentrations were higher in the western than in the eastern basin. The opposite was observed in the summer where the eastern basin was marked by higher AT and CT concentrations than in winter. The strong evaporation that takes place in this season along with the ultra-oligotrophy of the eastern basin determines the increase of both AT and CT concentrations
Analysis of Bidirectional Associative Memory using SCSNA and Statistical Neurodynamics
Bidirectional associative memory (BAM) is a kind of an artificial neural
network used to memorize and retrieve heterogeneous pattern pairs. Many efforts
have been made to improve BAM from the the viewpoint of computer application,
and few theoretical studies have been done. We investigated the theoretical
characteristics of BAM using a framework of statistical-mechanical analysis. To
investigate the equilibrium state of BAM, we applied self-consistent signal to
noise analysis (SCSNA) and obtained a macroscopic parameter equations and
relative capacity. Moreover, to investigate not only the equilibrium state but
also the retrieval process of reaching the equilibrium state, we applied
statistical neurodynamics to the update rule of BAM and obtained evolution
equations for the macroscopic parameters. These evolution equations are
consistent with the results of SCSNA in the equilibrium state.Comment: 13 pages, 4 figure
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Rationale and design of a phase II clinical trial of aspirin and simvastatin for the treatment of pulmonary arterial hypertension: ASA-STAT
Background - Pulmonary arterial hypertension (PAH) is a progressive disease which causes exercise limitation, heart failure, and death. Aspirin and simvastatin are highly effective and safe therapies for other cardiovascular diseases characterized by platelet activation and endothelial dysfunction, but have not been formally studied in PAH.
Methods - ASA-STAT is a phase II, randomized, double-blind, placebo-controlled 2 Ă 2 factorial clinical trial of aspirin and simvastatin in patients with PAH. A total of 92 subjects were to be randomized to aspirin or aspirin placebo and simvastatin or simvastatin placebo. The primary outcome is the distance walked in 6 min at 6 months after randomization. Secondary measures include brachial artery flow-mediated dilation, circulating biomarkers of platelet and endothelial function, functional class, quality-of-life, and time to clinical end points. The incidence of adverse events will be compared between treatment groups.
Screening and enrollment - We screened a total of 712 individuals with PAH. Sixty-five subjects were enrolled when the trial was terminated for futility in reaching the primary end point for simvastatin.
Conclusions - This study aims to determine whether aspirin or simvastatin have beneficial biologic or clinical effects in patients with PAH. The safety and side effects of these commonly prescribed cardiovascular drugs will also be assessed
Prognostic Significance of Biomarkers in Pulmonary Arterial Hypertension
Rationale: Pulmonary arterial hypertension (PAH) is a rare progressive disease of the pulmonary vasculature that is characterized by endothelial dysfunction, inflammation, and right ventricular dysfunction. Objectives: The main objective was to determine whether endothelial, inflammatory, and cardiac biomarkers would be associated with the World Health Organization functional assessment and survival in patients with PAH. Methods: We performed a retrospective cohort study of patients with PAH enrolled in the Randomized Clinical Trial of Aspirin and Simvastatin for Pulmonary Arterial Hypertension (ASA-STAT). Biomarkers (N-terminal fragment of pro-BNP [NT-pro-BNP], von Willebrand factor [vWF], soluble P selectin, C-reactive protein, total and high-density lipoprotein cholesterol, triglycerides, tumor necrosis factor, IL-6, ÎČ-thromboglobulin, and thromboxane B2) were measured at baseline. Patients from the study were followed until lung transplantation, death, or August 1, 2013. Ordinal logistic regression and Cox regression analyses were performed. Measurements and Main Results: Sixty-five patients with PAH were enrolled. The mean age was 51 years, and 86% were women. Higher vWF activity, lower high-density lipoprotein cholesterol, and higher thromboxane B2 levels were associated with worse World Health Organization functional class after adjustment for age, sex, and etiology of PAH. Higher NT-pro-BNP levels, lower vWF activity, and lower total cholesterol were associated with an increased risk of death or lung transplant after adjustment for age, sex, etiology of PAH, and 6-minute-walk distance. Conclusions: In patients with PAH, lower vWF activity and cholesterol levels and higher NT-pro-BNP levels at baseline were associated with an increased risk of death or transplantation. Clinical trial registered with www.clinicaltrials.gov (NCT00384865)
Quantum unsharpness and symplectic rigidity
We discuss a link between "hard" symplectic topology and an unsharpness
principle for generalized quantum observables (positive operator valued
measures). The link is provided by the Berezin-Toeplitz quantization.Comment: 26 pages, more preliminaries added, changes in the expositio
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