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

Voltage Stability of Converter-Interfaced Energy Storage Systems

This paper provides a sensitivity analysis of the interaction between the dynamic response of power systems and the unit commitment problem. A sub-hourly, mixed-integer linear programming Security Constrained Unit Commitment (SCUC) with a 24-hour rolling horizon is considered to cope with the uncertainty introduced by the large-scale penetration of nonsynchronous, stochastic renewable energy sources (RES). The SCUC is then integrated into Time Domain Simulations (TDS) and a sensitivity analysis with respect to different frequency controllers/machine parameters and different scheduling time intervals is carried out. Simulation results based on the 39-bus system show that shorter scheduling periods of the SCUC leads to lower operating cost and lower frequency variations.

Sensitivity Analysis of the Interaction between Power System Dynamics and Unit Commitment

This article addresses the execution cost of arithmetic operations with a focus on fuzzy arithmetic. Thanks to an appropriate representation format for fuzzy intervals, we show that it is possible to halve the number of operations and divide by 2 to 8 the memory requirements compared to conventional solutions. In addition, we demonstrate the benefit of some hardware features encountered in today’s accelerators (GPU) such as static rounding, memory usage, instruction-level parallelism (ILP), and thread-level parallelism (TLP). We then describe a library of fuzzy arithmetic operations written in CUDA and C++. The library is evaluated against traditional approaches using compute-bound and memory-bound benchmarks on Nvidia GPUs, with an observed performance gain of 2 to 20.

An Efficient Representation Format for Fuzzy Intervals Based on Symmetric Membership Functions

The paper introduces a novel approach to derive a dynamic model of devices with inclusion of Voltage Source Converter (VSC) devices suitable for transient angle and voltage stability analysis of power systems. With this aim, we treat the VSC as a nonlinear switched set of equations and apply a time-domain shooting method to define the behaviour of such model at the fundamental frequency of the system. Then the time-varying small-signal model of the VSC is derived through periodic small-signal analysis. The resulting model is defined in terms of a transfer function from which we can define a lumped equivalent circuit of the original device. The proposed approach is discussed and tested through the study of the transient response of a Static VAR Compensator (STATCOM) device connected to the well-known IEEE 14-bus system.

Periodic small-signal analysis as a tool to build transient stability models of VSC-based devices

Stochastic Differential Algebraic Equations (SDAEs) are used to model power systems. However, there is no universally accepted method to properly evaluate the stability of such models. The theoretical and numerical aspects of the computation of the largest Lyapunov Characteristic Exponent (LCE) for power systems with the inclusion of stochastic processes is discussed as a method to provide a measure of stability. A semi-implicit formulation of power systems is employed in order to exploit parallelism, sparsity and to have low memory requirements. Three case studies are considered, two based on the IEEE 14-bus system as well as a 1,479-bus model of the all island Irish transmission grid.

Federico Milano

Papers

Voltage Stability of Converter-Interfaced Energy Storage Systems

Sensitivity Analysis of the Interaction between Power System Dynamics and Unit Commitment

An Efficient Representation Format for Fuzzy Intervals Based on Symmetric Membership Functions

Periodic small-signal analysis as a tool to build transient stability models of VSC-based devices

Viable Computation of the Largest Lyapunov Characteristic Exponent for Power Systems