Connected operator

The goal of this work is to propose a set of techniques based on Mathematical Morphology to simplify or segment color images. Such simplification is done spatially or by quantization. The proposed methods apply the connected operators and morphological segmentation theories or extend them to color images.

This paper focuses on control strategies of Microgrid which consists of wind turbines, photovoltaic panels, batteries and super-capacitors with Hybrid DC and AC Buses. In grid-connected operation, voltage of DC bus is kept steady by inverter and voltage and frequency of AC bus are the same with utility grid. Energy Management System controls hybrid storage system to release or absorb power with the strategies according to grid condition, state of charge of batteries and super-capacitor, electricity price and so on. In islanded operation, voltage of DC bus is controlled by storage system and amplitude and frequency of AC-Bus voltage are regulated by parallel inverters with voltage-frequency or droop control strategy. In this paper, different control strategies in grid-connected and islanded operation are described which can keep power balanced and AC/DC bus stable. Simulation and experimental results are shown to verify the proposed control method.

This paper presents a new sensorless method for the vector control of Doubly-Fed Induction Machines (DFIMs) without using speed sensors or rotor position measurements. The proposed sensorless method is based on the Model Reference Adaptive System (MRAS) estimating the rotor position and speed from the machine rotor currents. The method is appropriate for both stand-alone and grid-connected operation of variable speed DFIMs. To design the MRAS observer with the appropriate dynamic response, a small signal model is derived. The sensitivity of the method for variation in the machine parameters is also analyzed. Speed catching on the fly and synchronization of the Doubly-Fed Induction Generator with the utility are also addressed. Experimental results obtained from a 3.5-kW prototype are presented and fully analyzed.

Pour déterminer la longueur de flambement ¢ ¡ d'un élément de structure, les méthodologies proposées à l'ingénieur relèvent de deux approches. La première passe par l'isolement de l'élément de la structure et la seconde déduit ¡ à partir du flambement global de la structure. Ces deux approches conduisent à des évaluations de ¡ quelquefois très éloignées. Cette divergence a même conduit à un paradoxe. Nous proposons de fixer pour définition de ¡ celle qui se réfère au cas idéal de la poutre isolée sous compression simple et d'arrêter son évaluation au second ordre. La formulation que nous en donnons conduit à une méthode destinée aux logiciels de calculs de structures pour un calcul systématique de ¡ . Nous proposons aussi une méthode simplifiée qui évite l'isolement de l'élément et conduit à une approximation de ¡ . Pour un chargement donné, cette méthode simplifiée utilise le flambement global de la structure dans la direction d'une compression localisée sur l'élément. Les deux méthodes sont comparées à travers l'analyse d'un poteau appartenant à différentes configurations (liaisons et chargements) d'un même portique.

This paper presents a new sensorless method for the vector control of doubly-fed induction machines (DFIMs) without using speed sensors or rotor position measurements. The proposed sensorless method is based on the model reference adaptive system (MRAS) estimating the rotor position and speed from the machine rotor currents. The method is appropriate for both stand-alone and grid-connected operation of variable

Pour déterminer la longueur de flambement ¢ ¡ d'un élément de structure, les méthodologies proposées à l'ingénieur relèvent de deux approches. La première passe par l'isolement de l'élément de la structure et la seconde déduit ¡ à partir du flambement global de la structure. Ces deux approches conduisent à des évaluations de ¡ quelquefois très éloignées. Cette divergence a même conduit à un paradoxe. Nous proposons de fixer pour définition de ¡ celle qui se réfère au cas idéal de la poutre isolée sous compression simple et d'arrêter son évaluation au second ordre. La formulation que nous en donnons conduit à une méthode destinée aux logiciels de calculs de structures pour un calcul systématique de ¡ . Nous proposons aussi une méthode simplifiée qui évite l'isolement de l'élément et conduit à une approximation de ¡ . Pour un chargement donné, cette méthode simplifiée utilise le flambement global de la structure dans la direction d'une compression localisée sur l'élément. Les deux méthodes sont comparées à travers l'analyse d'un poteau appartenant à différentes configurations (liaisons et chargements) d'un même portique.

This paper presents a seamless transition method for droop-controlled inverters to operate in both islanding and grid-connected modes. A local PLL and a virtual inductance are designed to ride through transient when the inverter switches between two modes with no synchronization. The proposed method can cooperatively work with well-developed droop controls so that the inverters are able to share load among them as well as subsist under transient events of the utility. Theoretical analysis and experimental results validate effectiveness of the proposed method.

3 The "mobile only/mobile primary" part of this analysis was presented at the W3C Workshop, Africa Perspective on the Role of Mobile Technologies in Fostering Social Development, Maputo, 1-2 April 2009. Opinions and analysis are the authors', and not necessarily those of Microsoft Corporation. Abstract The title of this workshop, 'beyond voice', is illustrative of one of the central questions currently surrounding mobile communication in the developing world. Put simply, there is a great deal of enthusiasm around the notion that a large group of users will access the internet for the first time via data enabled mobile handsets. Recent estimates from India, for example (Telecom Regulatory Authority of India, 2007), suggest there may be more mobile Internet connections than traditional PC Internet connections operational in the country. Concurrently, high-end smart phones promise browsing experiences which are steadily closing the gaps in speed and ease of use which have hampered earlier incarnations of the mobile internet, such as WAP. But the raw enthusiasm, the aggregate statistics, and the glossy marketing images from the top-end of handset markets fail to capture the reality of mobile internet use in the developing world. The crux of this paper's argument is that the research community knows comparatively little about this supposed community of users who access and use the Internet exclusively via mobile phones. We know little about who they are, how they discover and access the mobile internet, and how the mobile internet fits into their lives.

This paper presents a micro hydro power generation hardware setup, established via a research project at Gebze Institute of Technology (GIT), Turkey. This project is founded by the government and aims to increase utilization of potential for small, local hydro power generation. The hardware setup consists of a newly designed cross flow type hydro turbine, two different generators (asynchronous and synchronous up to 20 kW power range) and all equipment necessary for grid connected operation and islanding. The setup can be used for two purposes: primarily performance tests of newly designed micro hydro turbines, and research and development studies to provide new regulations and technical guidelines regarding to energy management and grid connected and island (stand-alone) operation which concern for distributed generation versatility. The hardware setup offers a similar environment to that of real site which can easily be adapted to the clients test and turbine evaluation requirements.

This paper describes the series connection of integrated gate commutated thyristors (IGCTs) using RC-snubbers. An experimental setup with a power rating of 6 kV, 4 kA is used to analyze the dynamic and static behavior of the series connected IGCTs in detail. The mechanism of thermal stabilization of series connected IGCTs is discussed. It is shown that a good voltage

An interesting and recently much studied generalization of the classical Schur class is the class of contractive operator-valued multipliers S(λ) for the reproducing kernel Hilbert space H(k d) on the unit ball B d ⊂ C d , where k d is the positive kernel k d (λ, ζ) = 1/(1 − λ, ζ) on B d. The reproducing kernel space H(K S) associated with the positive kernel K S (λ, ζ) = (I − S(λ)S(ζ) *) • k d (λ, ζ) is a natural multivariable generalization of the classical de Branges-Rovnyak canonical model space. A special feature appearing in the multivariable case is that the space H(K S) in general may not be invariant under the adjoints M * λ j of the multiplication operators M λ j : f (λ) → λ j f (λ) on H(k d). We show that invariance of H(K S) under M * λ j for each j = 1,. .. , d is equivalent to the existence of a realization for S(λ) of the form

This article discusses a new experimental way to measure the I-V characteristic curve of photovoltaic (PV) generators based on DC-DC converters. The obtained results show that the classical buck and boost converters are not capable of reproducing the whole I-V curve of PV generators and that the single-ended primary inductance converter (SEPIC) is optimal for this application. We propose a method based on SEPIC converters in parallel connection, operating in an interleaved mode. This method gives advantages with respect to the use of conventional methods.

This paper deals with the class of extensive operators in the lattice of partitions. These operators are merging techniques. They can be used as filtering tools or as segmentation algorithms. In the first case, they are known as connected operators and, in the second case, they are region growing techniques. This paper discusses the basic elements that have to be defined to create a merging algorithm: merging order, merging criterion and region model. This analysis highlights the similarity and differences between a filtering tool, such as a connected operator, and a segmentation algorithm. Taking benefit from the filtering and segmentation viewpoints, we propose a general merging algorithm that can be used to create new connected operators (in particular self-dual operators) and efficient segmentation algorithms (robust criteria and efficient implementation). Elsevier Science B.V. All rights reserved. PII S 0 1 6 5 -1 6 8 4 ( 9 8 ) 0 0 0 0 4 -8 diffe´rences entre un outil de filtrage, tel un ope´rateur connecte´, et un algorithme de segmentation. En prenant avantage des points de vue filtrage et segmentation, on propose un algorithme de fusion ge´ne´ral qui peut eˆtre utilise´pour cre´er de nouveaux ope´rateurs connecte´s (en particulier des ope´rateurs auto-duaux) ainsi que des algorithmes de segmentation efficaces (crite`res robustes et imple´mentation efficace).

This paper analyzes the use of high frequency signal injection methods for the sensorless control of doublyfed induction generators (DFIG). High frequency signal injection methods have been widely investigated for the sensorless control at very low speed and position control of induction machines (IM) and permanent magnet synchronous machines (PMSM). Most of these methods inject a high frequency voltage signal in the stator windings, which interacts with the machine asymmetries (saliencies), modulating the resulting stator high frequency currents, from which the rotor position is estimated. The use of these methods with doublyfed induction generators (DFIG) is studied in this paper, with special focus on two distinguishing features compared to the case of other types of three-phase machines: 1) it is feasible to inject the high frequency signal in the rotor, since the rotor windings are accessible and 2) as a consequence of this, it is possible to use the method with non-salient machines. 1 Index Terms-DFIG, high frequency signal injection, sensorless control. I.

Most work on high-performance work systems has examined only the direct relationship between a set of management practices and performance outcomes. This presumes that any connection operates through the incentive and motivational effects captured as`high-commitment' or`high-involvement' employee outcomes. No attempt has been made to examine the alternative, Labour Process conceptualization, which expects performance gains from new management practices to arise instead from work intensification, offloading of task controls, and increased job strain. Using data from WERS98, we tested models based on high-performance work systems and labour process approaches. Both were found wanting, and we consider the possible implications of these failures. This paper seeks to test the competing claims of theories advocating and criticizing so-called`high-performance work systems' (HPWS) in order to advance the debates about the nature and outcomes of emerging approaches to labour management. In an attempt to fill gaps in past research, the analysis explores linkages from HPWS practices to employee outcomes and via these to organizational performance. The paper utilizes data from the 1998 Workplace Employee Relations Survey (WERS98) to construct indicators of HPWS practices, of employee outcomes and of organizational performance as a means to explore associations between these phenomena.

Connectivity, the characterising feature of the Internet, requires the definition of access prices, transit charges, among connected operators. However, for many information exchanges, the network hierarchies in the Internet are not fixed: two providers can be simultaneously supplier and retailer, in a routing process, while being horizontally competitors in another. We study the impact of interconnection with transit demand on prices and profits for Internet Service Providers. These effects crucially depend on the degree of differentiation of the retail sector.

Point-to-point and point-to-multipoint connections operating at high frequencies become increasing importance in the near future wireless communication systems. These systems are applied in feeder network for future cellular mobile communication systems or BFWA (Broadband Fixed Wireless Access) networks. For accurate planning of the proposed microwave links the estimation of the CCDF (Complement Cumulative Distribution Function) of attenuation is highly important to achieve appropriate outage performance. In this work an N-state Markov chain model is investigated, which is used to generate attenuation time series influenced of those wireless links. With our proposed model very accurate realization of the physical fade process can be achieved. This work mainly focuses on the comparison of the generated and the measured attenuation time series, both the first and the second order statistics of attenuation will be examined.

This article discusses a new experimental way to measure the I-V characteristic curve of photovoltaic (PV) generators based on DC-DC converters. The obtained results show that the classical buck and boost converters are not capable of reproducing the whole I-V curve of PV generators and that the single-ended primary inductance converter (SEPIC) is optimal for this application. We propose a method based on SEPIC converters in parallel connection, operating in an interleaved mode. This method gives advantages with respect to the use of conventional methods.

Current solutions to interoperability remain limited with respect to highly dynamic and heterogeneous environments, where systems encounter one another spontaneously. In this chapter, we introduce the Connect architecture, which puts forward a fundamentally different method to tackle the interoperability problem. The philosophy is to observe networked systems in action, learn their behaviour and then dynamically generate mediator software which will connect two heterogeneous systems. We present a high-level overview of how Connect operates in practice and subsequently provide a simple example to illustrate the architecture in action.

The Image Foresting Transform (IFT) reduces optimal image partition problems from seed pixels into a shortest-path forest problem in a graph, whose solution can be obtained in linear time. It has allowed a unified and efficient approach to edge tracking, region growing, watershed transforms, multiscale skeletonization, and Euclidean distance transform. In this paper, we extend the IFT to introduce two connected operators: cutting-off-domes and filling-up-basins. The former simplifies grayscale images by reducing the height of its domes, while the latter reduces the depth of its basins. By automatically or interactively specifying seed pixels in the image and computing a shortest-path forest, whose trees are rooted at these seeds, the IFT creates a simplified image where the brightness of each pixel is associated with the length of the corresponding shortest-path. A label assigned to each seed is propagated, resulting a labeled image that corresponds to the watershed partitioning from markers. The proposed operators may also be used to provide regional image filtering and labeling of connected components. We combine the cutting-off-domes and filling-up-basins to implement regional minima/maxima, h-domes/basins, opening/closing by reconstruction, leveling, area opening/closing, closing of holes, and removal of pikes. Their applications are illustrated with respect to medical image segmentation.

This paper deals with a class of morphological operators called connected operators. These operators filter the signal by merging its flat zones. As a result, they do not create any new contours and are very attractive for filtering tasks where the contour information has to be preserved. This paper shows that connected operators work implicitly on a structured representation of the image made of flat zones. The max-tree is proposed as a suitable and efficient structure to deal with the processing steps involved in antiextensive connected operators. A formal definition of the various processing steps involved in the operator is proposed and, as a result, several lines of generalization are developed. First, the notion of connectivity and its definition are analyzed. Several modifications of the traditional approach are presented. They lead to connected operators that are able to deal with texture. They also allow the definition of connected operators with less leakage than the classical ones. Second, a set of simplification criteria are proposed and discussed. They lead to simplicity-, entropy-, and motion-oriented operators. The problem of using a nonincreasing criterion is analyzed. Its solution is formulated as an optimization problem that can be very efficiently solved by a Viterbi (1979) algorithm. Finally, several implementation issues are discussed showing that these operators can be very efficiently implemented

Visual quantification of parasitemia in thin blood films is a very tedious, subjective and time-consuming task. This study presents an original method for quantification and classification of erythrocytes in stained thin blood films infected with Plasmodium falciparum. The proposed approach is composed of three main phases: a preprocessing step, which corrects luminance differences. A segmentation step that uses the normalized RGB color space for classifying pixels either as erythrocyte or background followed by an Inclusion-Tree representation that structures the pixel information into objects, from which erythrocytes are found. Finally, a two step classification process identifies infected erythrocytes and differentiates the infection stage, using a trained bank of classifiers. Additionally, user intervention is allowed when the approach cannot make a proper decision. Four hundred fifty malaria images were used for training and evaluating the method. Automatic identification of infected erythrocytes showed a specificity of 99.7% and a sensitivity of 94%. The infection stage was determined with an average sensitivity of 78.8% and average specificity of 91.2%.

This paper focuses on the energy management system and stability of DC bus in both grid-connected and islanded operations in microgrid system. The microgrid system consists of wind turbines, photovoltaic panels, batteries and super-capacitors, also includes both AC and DC zones. Voltage of DC bus must be kept stable especially in islanded operation. In grid-connected operation voltage of DC bus is controlled by inverter. Real power from renewable energy generations and storage system can be transferred to AC zone through DC bus. In islanded operation, inverter must be controlled to keep magnitude and frequency of AC bus stable, so storage system is used to regulate voltage of DC bus. Simulation results in the paper show that voltage of DC bus can be kept steady and power can be kept balance with the strategy in microgrid system.

This paper focuses on the energy management system and stability of DC bus in both grid-connected and islanded operations in microgrid system. The microgrid system consists of wind turbines, photovoltaic panels, batteries and supercapacitors, also includes both AC and DC zones. Voltage of DC bus must be kept stable especially in islanded operation. In gridconnected operation voltage of DC bus is controlled by inverter. Real power from renewable energy generations and storage system can be transferred to AC zone through DC bus. In islanded operation, inverter must be controlled to keep magnitude and frequency of AC bus stable, so storage system is used to regulate voltage of DC bus. Simulation results in the paper show that voltage of DC bus can be kept steady and power can be kept balance with the strategy in microgrid system.

Visual quantification of parasitemia in thin blood films is a very tedious, subjective and time-consuming task. This study presents an original method for quantification and classification of erythrocytes in stained thin blood films infected with Plasmodium falciparum. The proposed approach is composed of three main phases: a preprocessing step, which corrects luminance differences. A segmentation step that uses the normalized RGB color space for classifying pixels either as erythrocyte or background followed by an Inclusion-Tree representation that structures the pixel information into objects, from which erythrocytes are found. Finally, a two step classification process identifies infected erythrocytes and differentiates the infection stage, using a trained bank of classifiers. Additionally, user intervention is allowed when the approach cannot make a proper decision. Four hundred fifty malaria images were used for training and evaluating the method. Automatic identification of infected erythrocytes showed a specificity of 99.7% and a sensitivity of 94%. The infection stage was determined with an average sensitivity of 78.8% and average specificity of 91.2%.

Among distributed energy resources, fuel cells show are particularly promising as they operate on multiple fuels with low to zero emissions, high efficiency (35-60%) and high reliability due to the limited number of moving parts. In this paper, a fuel cell model and control concept are presented for a fuel cell system intended for grid connected operation. First, the physical model of the fuel cell stack is described, to properly represent the slow dynamics associated with the gas flows and the fuel processor operation. Then, a suitable control architecture is presented for the overall system, its objective being to regulate the input fuel flow in order to meet a desirable output power demand, achieving at the same time a near optimal operation of the fuel cells. Then, the power conditioning system, including the DC/DC and DC/AC converters, is presented and typical waveforms are shown from its simulation. The fuel cell system investigated in this paper has a peak power of 1 kW at 50 V and a no load voltage of 95 V. The fuel cell model and its interface to the grid are implemented in Matlab/Simulink. I.

Power electronics based MicroGrids consist of a number of voltage source inverters (VSIs) operating in parallel. In this paper, the modeling, control design, and stability analysis of parallel connected three-phase VSIs are derived. The proposed voltage and current inner control loops and the mathematical models of the VSIs are based on the stationary reference frame. A hierarchical control scheme for the paralleled VSI system is developed comprising two levels. The primary control includes the droop method and the virtual impedance loops, in order to share active and reactive power. The secondary control restores the frequency and amplitude deviations produced by the primary control. Also, a synchronization algorithm is presented in order to connect the MicroGrid to the grid. Experimental results are provided to validate the performance and robustness of the parallel VSI system control architecture.

This paper deals with connected operators based on reconstruction process. Connected operators are filtering tools that act on the connected components of the space where the image is constant, the so-called "flat zones". Intuitively, connected operators can remove boundaries between flat zones but cannot add new boundaries nor shift existing contours. After reviewing the filtering strategy, new operators are proposed to perform size and motion simplification. In the case of size simplification, the proposed approach allows a better preservation the contrast of maxima or minima that have not been totally simplified by the filtering process. In the case of motion simplification, two applications are presented: motion detection for maxima/minima and sequence simplification to improve the coding efficiency of standard encoders.

We present a review of software-induced failures in commercial nuclear power plants (NPPs) and in several non-nuclear industries. We discuss the approach used for connecting operational events related to these failures and the insights gained from this review. In particular, we elaborate on insights that can be used to model this kind of failure in a probabilistic risk assessment (PRA) model. We present the conclusions reached in these areas.

This paper describes a framework of map image analysis and presentation of the semantic information to blind users using alternative modalities (i.e. haptics and audio). The resulting haptic-audio representation of the map is used by the blind for navigation and path planning purposes. The proposed framework utilizes novel algorithms for the segmentation of the map images using morphological filters that are able to provide indexed information on both the street network structure and the positions of the street names in the map. Next, off-the-shelf OCR and TTS algorithms are utilized to convert the visual information of the street names into audio messages. Finally, a grooved-line-map representation of the map network is generated and the blind users are able to investigate it using a haptic device. While navigating, audio messages are displayed providing information about the current position of the user (e.g. street name, crossroad notification and so on). Experimental results illustrate that the proposed system is considered very promising for the blind users and has been reported to be a very fast means of generating maps for the blind when compared to other traditional methods like Braille images.

We give in this paper which is the third in a series of four a theory of covariant derivatives of representatives of multivector and extensor fields on an arbitrary open set U ⊂ M, based on the geometric and extensor calculus on an arbitrary smooth manifold M. This is done by introducing the notion of a connection extensor field γ defining a parallelism structure on U ⊂ M, which represents in a well-defined way the action on U of the restriction there of some given connection ∇ defined on M. Also we give a novel and intrinsic presentation (i.e. one that does not depend on a chosen orthonormal moving frame) of the torsion and curvature fields of Cartan's theory. Two kinds of Cartan's connection operator fields are identified, and both appear in the intrinsic Cartan's structure equations satisfied by the Cartan's torsion and curvature extensor fields. We introduce moreover a metrical extensor g in U corresponding to the restriction there of given metric tensor g define...

In this paper a multiscale study based on the use of morphological connected transformations is presented. In particular, the morphological opening and closing by reconstruction are used as connected transformations. These transformations have the characteristic of preserving contours without introducing new information, in addition to smoothing the processed image as the size of the structuring element increases. Due to this, both connected filters and the identity are used as primitives to introduce two operators that allow a multiscale treatment to the processed image in accordance with the scale parameter. The multiscale morphological operators are called opening–closing by reconstruction and closing–opening by reconstruction, respectively. In the case of the opening–closing by reconstruction transformation, the propagation of extrema when the structuring element enlarges has an interesting behavior. In addition, the fingerprints of the image given as a function of regional maxima, regional minima and scale parameter are defined. Finally, the proposals of this work are illustrated with some examples.

This paper deals with the class of extensive operators in the lattice of partitions. These operators are merging techniques. They can be used as filtering tools or as segmentation algorithms. In the first case, they are known as connected operators and, in the second case, they are region growing techniques. This paper discusses the basic elements that have to be defined to create a merging algorithm: merging order, merging criterion and region model. This analysis highlights the similarity and differences between a filtering tool, such as a connected operator, and a segmentation algorithm. Taking benefit from the filtering and segmentation viewpoints, we propose a general merging algorithm that can be used to create new connected operators (in particular self-dual operators) and efficient segmentation algorithms (robust criteria and efficient implementation). Elsevier Science B.V. All rights reserved. PII S 0 1 6 5 -1 6 8 4 ( 9 8 ) 0 0 0 0 4 -8 diffe´rences entre un outil de filtrage, tel un ope´rateur connecte´, et un algorithme de segmentation. En prenant avantage des points de vue filtrage et segmentation, on propose un algorithme de fusion ge´ne´ral qui peut eˆtre utilise´pour cre´er de nouveaux ope´rateurs connecte´s (en particulier des ope´rateurs auto-duaux) ainsi que des algorithmes de segmentation efficaces (crite`res robustes et imple´mentation efficace).

This paper presents a control strategy of a hybrid fuel cell/battery distributed generation (HDG) system in distribution systems. The overall structure of the HDG system is given, dynamic models for the solid oxide fuel cell (SOFC) power plant, battery bank and its power electronic interfacing are briefly described, and controller design methodologies for the power conditioning units and fuel cell to control the power flow from the hybrid power plant to the utility grid are presented. To distribute the power between the fuel cell power plant and the battery energy storage, a neuro-fuzzy controller has been developed. Also, for controlling the active and reactive power independently in distribution systems, the current control strategy based on two fuzzy logic controllers has been presented. A Matlab/Simulink simulation model is developed for the HDG system by combining the individual component models and their controllers. Simulation results show the overall system performance including load-following and power management of the HDG system.

This paper proposes a sensorless control strategy for doubly-fed induction generators (DFIGs) in variable-speed wind turbine systems (WTS). The proposed scheme uses an extended Kalman filter (EKF) for the estimation of rotor speed and rotor position. Moreover, the EKF is used to estimate the mechanical torque of the generator to allow for maximum power point tracking control for wind speeds below the nominal wind speed. For EKF design, the nonlinear state space model of the DFIG is derived. Estimation and control performance of the proposed sensorless control method are illustrated by simulation results at low, high, and synchronous speed. The designed EKF is robust to machine parameter variations within reasonable limits. Finally, the performances of the EKF and a model reference adaptive system (MRAS) observer are compared for time-varying wind speeds.

The Image Foresting Transform (IFT) reduces optimal image partition problems from seed pixels into a shortest-path forest problem in a graph, whose solution can be obtained in linear time. It has allowed a unified and efficient approach to edge tracking, region growing, watershed transforms, multiscale skeletonization, and Euclidean distance transform. In this paper, we extend the IFT to introduce two connected operators: cutting-off-domes and filling-up-basins. The former simplifies grayscale images by reducing the height of its domes, ...

This paper presents a control strategy of a hybrid fuel cell/battery distributed generation (HDG) system in distribution systems. The overall structure of the HDG system is given, dynamic models for the solid oxide fuel cell (SOFC) power plant, battery bank and its power electronic interfacing are briefly described, and controller design methodologies for the power conditioning units and fuel cell to control the power flow from the hybrid power plant to the utility grid are presented. To distribute the power between the fuel cell power plant and the battery energy storage, a neuro-fuzzy controller has been developed. Also, for controlling the active and reactive power independently in distribution systems, the current control strategy based on two fuzzy logic controllers has been presented. A Matlab/Simulink simulation model is developed for the HDG system by combining the individual component models and their controllers. Simulation results show the overall system performance including load-following and power management of the HDG system.

The Connected Component Tree (CCT)-based operators play a central role in the development of new algorithms related to image processing applications such as pattern recognition, video-surveillance or motion extraction. The CCT construction, being a time consuming task (about 80% of the application time), these applications remain far-off mobile embedded systems. This paper presents its efficient FPGA implementation suited for embedded systems. Three main contributions are discussed: an efficient data structure proposal adapted to representing the CCT in embedded systems, a memory organization suitable for FPGA implementation by using on-chip memory and a customizable hardware accelerator architecture for CCT-based applications.

A method for the automatic segmentation, recognition and measurement of neuronal myelinated fibers in nerve histological sections is presented. In this method, the fiber parameters i.e. perimeter, area, position of the fiber and myelin sheath thickness are automatically computed. Obliquity of the sections may be taken into account. First, the image is thresholded to provide a coarse classification between myelin and non-myelin pixels. Next, the resulting binary image is further simplified using connected morphological operators. By applying semantic rules to the zonal graph axon candidates are identified. Those are either isolated or still connected. Then, separation of connected fibers is performed by evaluating myelin sheath thickness around each candidate area with an Euclidean distance transformation. Finally, properties of each detected fiber are computed and false positives are removed. The accuracy of the method is assessed by evaluating missed detection, false positive ratio and comparing the results to the manual procedure with sampling. In the evaluated nerve surface, a 0.9% of false positives was found, along with 6.36% of missed detections. The resulting histograms show strong correlation with those obtained by manual measure. The noise introduced by this method is significantly lower than the intrinsic sampling variability. This automatic method constitutes an original tool for morphometrical analysis.

Routing and wavelength assignment under availability constraints has been extensively researched recently. Availability (or more precisely, steady-state availability) can be defined as the average probability of a connection operating over a time window that tends to infinity. However, service level agreements (SLAs) commit a minimum connection uptime fraction over a finite contract duration. This random variable is known in reliability engineering as interval availability. If the minimum agreed interval availability is not honored, the service provider is penalized. In order to balance the risk of non-compliance fines against asset protection costs, network planners must know the interval availability distribution. However, its estimation with existing numerical techniques is computationally expensive, motivating the search for approximate analytical methods. Under the hypotheses of Poissonian node and link failures and repairs, and assuming no more than two link failures or one node failure in the network, we propose, for connections protected by shared or dedicated methods: an approximate Markov model that allows the derivation of a closed-form expression for the connection steady-state availability; under the approximate Markov model, analytical bounds on the interval availability distribution. The proposed methods are validated by discrete-event simulations of an Italian network.

This paper proposes an integrated wind-photovoltaic-battery hybrid system that features a simple power management strategy, requires a lower number of power-electronic converters, and eliminates the need for dump loads. Thus, it is expected to offer a lower cost and higher efficiency, and to enable easier integration with distribution networks, as compared with a set of three stand-alone system. The power management strategy of the proposed hybrid system enables (1) rapid control of the wind and photovoltaic (PV) power outputs for tightly regulating the battery current, (2) off-grid operation with blackstart capability, (3) grid-connected operation, and (4) safe transition from the grid-connected mode to the off-grid mode, and vice versa, without a need for communications with the host grid. Further, the proposed hybrid system is expected to have plug-and-play and power sharing capabilities and, therefore, suited for multi-generator remote electrification systems. The effectiveness of the proposed hybrid system is demonstrated through time-domain simulation studies in the PSCAD/EMTDC software environment.

Volpin, and seminar participants at the Darden conference on emerging markets, the Indian School of Business, the University of Amsterdam, and the World Bank for detailed discussions and/or comments on earlier drafts, and David Samuels for sharing part of the data on campaign contributions. The findings, interpretations, and conclusions expressed in this paper are entirely those of the authors. They do not represent the views of the International Monetary Fund, the World Bank, their Executive Directors, or the countries they represent.

In this paper, we define a connected operator that either fills or retains the holes of the connected sets depending on application-specific criteria that are increasing in the set theoretic sense. We refer to this class of connected operators as inclusion filters, which are shown to be increasing, idempotent, and self dual (gray-level inversion invariance). We demonstrate self duality for 8-adjacency on a discrete Cartesian grid. Inclusion filters are defined first for binary-valued images, and then the definition is extended to grayscale imagery. It is also shown that inclusion filters are levelings, a larger class of connected operators. Several important applications of inclusion filters are demonstrated-automatic segmentation of the lung cavities from magnetic resonance imagery, user interactive shape delineation in content-based image retrieval, registration of intravital microscopic video sequences, and detection and tracking of cells from these sequences. The numerical performance measures on 100-cell tracking experiments show that the use of inclusion filter improves the total number of frames successfully tracked by five times and provides a threefold reduction in the overall position error.

... 1, JANUARY 2008 Sensorless Control of Doubly-Fed Induction Generators Using a Rotor-Current-Based MRAS Observer Rubén Peña, Member, IEEE, Roberto Cárdenas, Senior Member, IEEE, José Proboste, Greg Asher, Fellow, IEEE, and Jon Clare, Senior Member, IEEE ...