Nonlinear control of a grid connected hybrid energetic systems (HES) based on photovoltaic-fuel cells distributed power generation systems

This paper presents a discrete-time integral sliding mode control for a grid connected hybrid energetic systems (HES) based on photovoltaic-Solid oxide fuel cell (SOFC) for distributed power generation systems. The proposed HES systems employ solid oxide fuel cell (SOFC) and photovoltaic panels as main sources, supercapacitors as complementary sources, and controlled DC-DC boost converter and three levels NPC inverter. A maximum power point tracking (MPPT) control is used in order to maximize the power of the photovoltaic system. The proposed control consists of a power management grid interface inverter transferring the energy from the hybrid sources into the grid by controlling the main utility grid and the common DC voltage active and reactive power. The obtained simulation results show the effectiveness and robustness of the proposed control strategy. Keywords: Hybrid Energetic Systems (HES), Solid Oxide Fuel Cell (SOFC), Photovoltaic (PV), Sliding Mode Control, Maximum Power Point Tracking (MPPT), Grid power management

On the Spatial Structure of the Antenna Electromagnetic Near Field

Abstract This paper presents a general theory of the antenna near field in the spatial domain. The approach is based on using the Wilcox expansion of the radiated field to define a set of asymptotic spherical regions covering the entire exterior space of the antenna problem. Careful examination of the energy expression within this picture revealed the rich and complex interaction mechanisms between the various spherical regions indicated above. The multipole expansion is then utilized to construct nonrecursively the full near field in the exterior region starting from the far field only. The analysis led to interesting theorems regrading energy exchange processes in the near zone and also to a completely analytical evaluation of the antenna reactive energy in terms of the TE and TM modes of the antenna system. The Structure of the Antenna Near Field in the Spatial Domain We assume that an arbitrary electric current J(r) exists inside a volume V 0 enclosed by the surface S 0 . Let the antenna be surrounded by an infinite, isotropic, and homogenous space with permittivity ε and permeability µ. The antenna current will radiate electromagnetic fields everywhere and we are concerned with the region outside the source volume V 0 . We consider two characteristic regions. The first is the region V enclosed by a spherical surface S and this will be the setting for the near fields. The second region V ∞ is the one enclosed by the spherical surface S ∞ taken at infinity and it corresponds to the far fields. The complex Poynting theorem states that ∇ · S = −(1/2)J * · E + 2iω (w h − w e ), where the complex Poynting vector is defined as S = (1/2) E × H * and the magnetic and electric energy densities are given, respectively, by w e = (1/4)εE · E * and w h = (1/4)µH · H * , and ω is the radian frequency where the radiated power is defined as P rad = Re S ds 1 2 (E × H * ). The result above will be taken up again in Section 3. In the remaining part of this section we try to gain a more detailed insight into the nature of the near field that goes beyond the simple picture presented by (1). We consider the fields generated by the antenna lying in the intermediate zone, i.e., the interesting case between the far zone kr → ∞ and the static zone kr → 0. We aim to attain a conceptual insight into the nature of the near field by mapping out its inner structure in details. Since the fields in the exterior region satisfy the homogenous Helmholtz equation, we can expand the electric and magnetic fields as [1] where A n and B n are vector angular functions dependent on the far-field radiation pattern of the antenna and k = ω √ εµ is the wavenumber. 1 Let us then divide the entire exterior region surrounding the antenna into an infinite number of spherical layers. The outermost layer R 0 is identified with the far zone while the innermost layer R ∞ is defined as the minimum sphere totally enclosing the antenna current distribution. In between these two regions, an infinite number of layers exists, each corresponding to a term in the Wilco

To Perform Road Signs Recognition for Autonomous Vehicles Using Cascaded Deep Learning Pipeline

Autonomous vehicle is a vehicle that can guide itself without human conduction. It is capable of sensing its environment and moving with little or no human input. This kind of vehicle has become a concrete reality and may pave the way for future systems where computers take over the art of driving. Advanced artificial intelligence control systems interpret sensory information to identify appropriate navigation paths, as well as obstacles and relevant road signs. In this paper, we introduce an intelligent road signs classifier to help autonomous vehicles to recognize and understand road signs. The road signs classifier based on an artificial intelligence technique. In particular, a deep learning model is used, Convolutional Neural Networks (CNN). CNN is a widely used Deep Learning model to solve pattern recognition problems like image classification and object detection. CNN has successfully used to solve computer vision problems because of its methodology in processing images that are similar to the human brain decision making. The evaluation of the proposed pipeline was trained and tested using two different datasets. The proposed CNNs achieved high performance in road sign classification with a validation accuracy of 99.8% and a testing accuracy of 99.6%. The proposed method can be easily implemented for real time application

A Novel Dataset For Intelligent Indoor Object Detection Systems

Indoor Scene understanding and indoor objects detection is a complex high-level task for automated systems applied to natural environments. Indeed, such a task requires huge annotated indoor images to train and test intelligent computer vision applications. One of the challenging questions is to adopt and to enhance technologies to assist indoor navigation for visually impaired people (VIP) and thus improve their daily life quality. This paper presents a new labeled indoor object dataset elaborated with a goal of indoor object detection (useful for indoor localization and navigation tasks). This dataset consists of 8000 indoor images containing 16 different indoor landmark objects and classes. The originality of the annotations comes from two new facts taken into account: (1) the spatial relationships between objects present in the scene and (2) actions possible to apply to those objects (relationships between VIP and an object).This collected dataset presents many specifications and strengths as it presents various data under various lighting conditions and complex image background to ensure more robustness when training and testing objects detectors. The proposed dataset, ready for use, provides 16 vital indoor object classes in order to contribute for indoor assistance navigation for VIP

The Palestinian health research system:who orchestrates the system, how and based on what? A qualitative assessment

Abstract Background In 2011, the WHO Eastern Mediterranean Region committee launched a strategy for scaling up research in the region to address the countries’ health needs through formulating and analysing the National Health Research System (HRS). Stewardship comprises three functions, namely governance, policy and priorities, and is a central pillar of this system to ensure a well-organised and functioning HRS. This study aims to examine the perceptions of the HRS performers to understand these functions and to generate insights for system strengthening. Methods The study was carried out in Palestine, targetting three sectors in the health field, including relevant governmental health institutions, schools of public health, and major local and international health agencies. The data were collected through 52 in-depth interviews (IDIs) and 6 focus group discussions (FGDs) with policy-makers, academics, directors, and experts. Participants and institutions were selected purposively based on a set of criteria and peer review. Results A total of 104 experts participated in the IDIs (52 participants) and FGDs (52 participants in 6 FGDs), highlighting that stewardship functions remain problematic and insufficiently performed, mainly due to a missing health research structural and regulatory framework and dispersed health research work. Despite the limited good practices, the majority of the participants described the Ethical Review and Clearance as weak due to the lack of an agreed-upon national committee and procedural quality and ethics guidelines for non-compliance. A policy or strategy dedicated to health research is lacking. The exercises of research priority-setting appear to be evolving despite the lack of consensus and the low levels of knowledge and experience in research prioritisation. Common gaps, such as weak political will and capacity support, the absence of a national unified regulating body, and the indirect effects of political conditions on strengthening the HRS as well as other sectors, also emerged. Conclusions The stewardship functions of the Palestinian HRS remain weak along with substantial political, structural, and resources and capacity gaps. The study emphasises the imperative need to initiate strategic efforts led by the MOH and the Palestinian National Institute of Public Health alongside with other players to strengthen a national HRS through improving the stewardship functions. To achieve this, attention and support of decision-makers, involvement, mobilisation and strategic dialogue are indispensable, in order to embark on building a well-regulated and coordinated structure, operational research policy, and prioritisation of essential research