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

This work discusses control aspects and stability issues of future transmission networks. With this aim, several scenarios are considered, and their behavior is compared with that of a standard power system. In particular, voltage, transient, and frequency stability issues are examined. Scenarios involve changes in the generation devices, transmission lines, and transient behavior of loads. In future power networks, generators are assumed to be distributed and decoupled from the grid through voltage source converters. While AC transmission lines cannot be realistically fully substituted with other transmission devices, a high penetration of VSC-HVDC devices and superconducting corridors is considered. Finally, loads are considered “active,” that is, able to regulate the frequency and equipped with local energy resources and storage systems. The case study, which is based on the IEEE 14-bus system, provides a comprehensive comparison of the behavior and the stability of the conventional and future power systems.


Keywords:

voltage stability;
transient stability;
frequency stability;
voltage source converters (VSCs);
reactive power compensation;
load frequency control;
energy storage systems

Control and Stability of Future Transmission Networks

This paper discusses two quantitative and complementary approaches to evaluate the participation of synchronous generators and interconnection buses on local bus frequency variations during electromechanical transients. Both approaches are based on the concept of frequency divider formula recently proposed by the authors on these transactions. A thorough comparison of the two approaches is provided considering several scenarios and three networks, namely the New England 39-bus test system, the all-island 1479-bus Irish transmission system, and the ENTSO-E 21 177-bus transmission system.

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Frequency Participation Factors

This paper proposes a novel technique for representing system security constraints that properly include voltage stability limits in the operation of competitive electricity markets. The market-clearing algorithm is modeled as a voltage stability constrained optimal power flow (OPF) problem, while the distance to the closest critical power flow solution is represented by means of a loading parameter and evaluated using a continuation power flow (CPF) technique. Sensitivities obtained at the OPF step are used to estimate power directions for the CPF method, while the CPF analysis provides the loading parameter to be used in the OPF problem based on an N-1 contingency criterion. The OPF and the CPF steps are repeated until the maximum loading parameter is found, thus providing optimal solutions considering both proper market conditions and security margins. Two benchmark systems with both supply and demand bidding are used to illustrate and test the proposed technique

Sensitivity-Based Security-Constrained OPF Market Clearing Model

The paper provides a novel framework to study the accuracy and stability of numerical integration schemes when employed for the time domain simulation of power systems. A matrix pencil-based approach is adopted to evaluate the error between the dynamic modes of the power system and the modes of the approximated discrete-time system arising from the application of the numerical method. The proposed approach can provide meaningful insights on how different methods compare to each other when applied to a power system, while being general enough to be systematically utilized for, in principle, any numerical method. The framework is illustrated for a handful of well-known explicit and implicit methods, while simulation results are presented based on the WSCC 9-bus system, as well as on a 1,479-bus dynamic model of the All-Island Irish Transmission System.

Small-Signal Stability Analysis of Numerical Integration Methods

This paper presents a general adaptive control scheme for regulating power system devices. The main idea of the paper is to build a fictitiou set of differential equations starting from a function that satisfie Lyapunov's second stability criterion. In such a way, the fictitiou set of differential equations surely converge to a stable equilibrium point. We propose to use this mathematical tool to control arbitrary power system devices and to improve the transient behavior of the whole network. We apply the proposed technique to stabilize synchronous machine oscillations and show that the proposed controller provides better results than the conventional power system stabilizer. Finally, the paper provides several remarks on the applicability of the proposed technique.

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Federico Milano

Papers

Control and Stability of Future Transmission Networks

Frequency Participation Factors

Sensitivity-Based Security-Constrained OPF Market Clearing Model

Small-Signal Stability Analysis of Numerical Integration Methods

A general power system control technique based on Lyapunov's function