다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

MATPOWER is an open-source Matlab-based power system simulation package that provides a high-level set of power flow, optimal power flow (OPF), and other tools targeted toward researchers, educators, and students. The OPF architecture is designed to be extensible, making it easy to add user-defined variables, costs, and constraints to the standard OPF problem. This paper presents the details of the network modeling and problem formulations used by MATPOWER, including its extensible OPF architecture. This structure is used internally to implement several extensions to the standard OPF problem, including piece-wise linear cost functions, dispatchable loads, generator capability curves, and branch angle difference limits. Simulation results are presented for a number of test cases comparing the performance of several available OPF solvers and demonstrating MATPOWER's ability to solve large-scale AC and DC OPF problems.

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MATPOWER: Steady-State Operations, Planning, and Analysis Tools for Power Systems Research and Education

We explore in this chapter questions of existence and uniqueness for solutions to stochastic differential equations and offer a study of their properties. This endeavor is really a study of diffusion processes. Loosely speaking, the term diffusion is attributed to a Markov process which has continuous sample paths and can be characterized in terms of its infinitesimal generator.

Stochastic Differential Equations

Objective
To present the International Parkinson and Movement Disorder Society (MDS) Clinical Diagnostic Criteria for Parkinson9s disease.
Background
Although several diagnostic criteria for Parkinson9s disease have been proposed, none have been officially adopted by an official Parkinson society. Moreover, the commonest-used criteria, the UK brain bank, were created more than 25 years ago. In recognition of the lack of standard criteria, the MDS initiated a task force to design new diagnostic criteria for clinical Parkinson9s disease.
Methods/Results
The MDS-PD Criteria are intended for use in clinical research, but may also be used to guide clinical diagnosis. The benchmark is expert clinical diagnosis; the criteria aim to systematize the diagnostic process, to make it reproducible across centers and applicable by clinicians with less expertise. Although motor abnormalities remain central, there is increasing recognition of non-motor manifestations; these are incorporated into both the current criteria and particularly into separate criteria for prodromal PD. Similar to previous criteria, the MDS-PD Criteria retain motor parkinsonism as the core disease feature, defined as bradykinesia plus rest tremor and/or rigidity. Explicit instructions for defining these cardinal features are included. After documentation of parkinsonism, determination of PD as the cause of parkinsonism relies upon three categories of diagnostic features; absolute exclusion criteria (which rule out PD), red flags (which must be counterbalanced by additional supportive criteria to allow diagnosis of PD), and supportive criteria (positive features that increase confidence of PD diagnosis). Two levels of certainty are delineated: Clinically-established PD (maximizing specificity at the expense of reduced sensitivity), and Probable PD (which balances sensitivity and specificity).
Conclusion
The MDS criteria retain elements proven valuable in previous criteria and omit aspects that are no longer justified, thereby encapsulating diagnosis according to current knowledge. As understanding of PD expands, criteria will need continuous revision to accommodate these advances. Disclosure: Dr. Postuma has received personal compensation for activities with Roche Diagnostics Corporation and Biotie Therapies. Dr. Berg has received research support from Michael J. Fox Foundation, the Bundesministerium fur Bildung und Forschung (BMBF), the German Parkinson Association and Novartis GmbH.

MDS Clinical Diagnostic Criteria for Parkinson's Disease (S19.001)

Numerical Initial Value Problems in Ordinary Differential Equations

The paper proposes a technique to locate the source of forced oscillations in power systems. The only requirement is the availability of bus frequency measurements as obtained, for example, from phasor measurement units. The proposed technique is model-agnostic, optimization-free, non-confidential, and independent from the source and the frequency of the forced oscillations. Accuracy and robustness with respect to noise are demonstrated through two examples based on the IEEE 14-bus and New England 39-bus systems, as well as a case study based on a 1,479-bus dynamic model of the all-island Irish transmission system.

Source Location of Forced Oscillations based on Bus Frequency Measurements

This paper discusses the impact of energy storage systems (ESSs) on long-term power system frequency deviations originated by real-time electricity markets with short dispatch periods. The goal of the paper is to evaluate whether and under which conditions ESSs are effective in reducing these frequency deviations. With this aim, the paper first discusses a dynamic market model with inclusion of ESSs. Then, it provides a comprehensive sensitivity analysis of the ESS control parameters based on time domain simulations. Results indicate that ESSs can significantly reduce the long-term frequency deviations. However, the capacities of the ESSs as well as the deadband and droop coefficient of the ESS controllers have to be carefully designed to avoid the outbreak of unexpected dynamic behaviors.

Contribution of Energy Storage Systems to Long-Term Power System Dynamic Performance

The One-Step Delay Approximation (OSDA) technique consists in delaying certain variables of a power system model with time delays of magnitude equal to the step size of the Time Domain Integration (TDI). The objective of the OSDA is to reduce the mutual coupling of the system's equations and the density of the Jacobian matrix that needs to be factorized at each step of the TDI. In turn, the OSDA leads to a simulation speedup but may worsen the accuracy of the results. This paper provides a novel matrix-pencil based approach to assess the OSDA technique in terms of its impact on the accuracy and numerical stability of the TDI of power systems. The case study illustrates the proposed approach through the WSCC 9-bus benchmark system.

On the Numerical Stability and Accuracy of One-Step Delay Approximations

The letter describes a novel, continuum-based approach, to capture the evolution of electromechanical dynamics in a power network following a disturbance. Such approach is based on the frequency divider formula (FDF), which was recently proposed by the third author. A key point in obtaining the frequency divider formula (FDF) as a consequence of a continuum, is to show that the spatial rate of change, at a given time, of the frequency along a lossless line is constant. The proposed derivation is then compared with the electromechanical wave approach (EWA), which has been discussed in the literature in a variety of hues and is aimed at modeling the propagation in a power system of frequency oscillations following a disturbance. The discussion illustrates similarities and differences between FDF and electromechanical wave approach (EWA).

https://doi.org/10.1109/tpwrs.2022.3207058

Federico Milano

Papers

Source Location of Forced Oscillations based on Bus Frequency Measurements

Contribution of Energy Storage Systems to Long-Term Power System Dynamic Performance

On the Numerical Stability and Accuracy of One-Step Delay Approximations

Frequency Divider as a Continuum

Technical and Economic Aspects