The paper describes a variable speed wind generation system where fuzzy logic principles are used for light load efficiency improvement and optimization. A squirrel cage induction generator feeds the power to an improved topology of matrix converter which pumps power to a utility grid or can supply to an autonomous system. The power factor at the interface with the grid is controlled by the mat...

Given a knot presented in a grid diagram, we construct a CW complex which has one cell for each generator of the grid chain complex, and whose homology is the grid homology. This space is welldefined, and its stable homotopy type is a knot invariant. Thus to each knot, we can associate an invariant spectrum, whose F2 homology is the knot Floer homology over F2. 1991 Mathematics Subject Classifi...

This paper focuses on PSS/E modeling of wind farms of Doubly-fed Induction Generator (DFIG) type and their impact on issues of power system operation. Since Wind Turbine Generators (WTG) don’t have the same characteristics as synchronous generators, the appropriate modeling of wind farms is essential for transmission system operators to analyze the best options of transmission grid reinforcemen...

Understanding large Grid platform configurations and generating representative synthetic configurations is critical for Grid computing research. This paper presents an analysis of existing resource configurations and proposes a Grid platform generator that synthesizes realistic configurations of both computing and communication resources. Our key contributions include the development of statist...

We present implementation details and analyze convergence of a two-grid solver forming the core of the fully automatic hp-adaptive strategy for elliptic problems. The solver delivers a solution for a fine grid obtained from an arbitrary coarse hp-grid by a global hp-refinement. The classical V-cycle algorithm combines an overlapping block Jacobi smoother with optimal relaxation, and a direct so...

Nowadays, the doubly-fed induction generators (DFIGs) based wind turbines (WTs) are the dominant type of WTs connected to grid. Traditionally the back-to-back converters are used to control the DFIGs. In this paper, an Indirect Matrix Converter (IMC) is proposed to control the generator. Compared with back-to-back converters, IMCs have numerous advantages such as: higher level of robustness, re...

This paper presents a new type of chaotic encryption system based on combined chaotic mapping pseudo-random number generator, Hash Table, and elliptic curve. In this program, the elliptic curve algorithm is used for the key distribution. After the linear transformation, the original chaotic sequence generated by drive system can be combined to chaotic mapping, converted to an encryption key seq...

In this paper we establish the well-posedness in C([0,∞); [0,1]d ), for each starting point x ∈ [0,1]d , of the martingale problem associated with a class of degenerate elliptic operators which arise from the dynamics of populations as a generalization of the Fleming–Viot operator. In particular, we prove that such degenerate elliptic operators are closable in the space of continuous functions ...

Many E-Commerce applications are characterized, for instance, by their demand for confidential data exchange via public communication networks (e.g., Internet). These data exchanges must be protected from fraudulent access by third parties. One way is to use public key crypto systems based on elliptic curves. They gain more and more acceptance, since they provide high security in spite of their...

Digital signature schemes often use domain parameters such as prime numbers or elliptic curves. They can be subject to security threats when they are not treated like public keys. In this paper we formalize the notion of “signature scheme with domain parameter” together with a new adversarial model: the “domain parameter shifting attack”. We take ECDSA as a case study. We make a domain paramete...