Genetic algorithms for satellite scheduling problems

Recently there has been a growing interest in mission operations scheduling problem. The problem, in a variety of formulations, arises in management of satellite/space missions requiring efficient allocation of user requests to make possible the communication between operations teams and spacecraft systems. Not only large space agencies, such as ESA (European Space Agency) and NASA, but also smaller research institutions and universities can establish nowadays their satellite mission, and thus need intelligent systems to automate the allocation of ground station services to space missions. In this paper, we present some relevant formulations of the satellite scheduling viewed as a family of problems and identify various forms of optimization objectives. The main complexities, due highly constrained nature, windows accessibility and visibility, multi-objectives and conflicting objectives are examined. Then, we discuss the resolution of the problem through different heuristic methods. In particular, we focus on the version of ground station scheduling, for which we present computational results obtained with Genetic Algorithms using the STK simulation toolkit.Peer ReviewedPostprint (published version

IEEE Access special section editorial: optical wireless technologies for 5G communications and beyond

Wide bandwidth and dense spatial reuse are of extreme importance for future wireless communication networks, including 5G and beyond. In particular, these properties are important to enable future wireless networks to cope with the explosive increase in the demand for high data-rate communications. Optical wireless communications (OWC) is a promising technology for achieving this goal due to the abundant reusable license-free optical spectrum. This potential of OWC attracted significant global attention both from communications and optoelectronics viewpoints, and continues to do so

A Survey on Communication Networks for Electric System Automation

Published in Computer Networks 50 (2006) 877–897, an Elsevier journal. The definitive version of this publication is available from Science Direct. Digital Object Identifier:10.1016/j.comnet.2006.01.005In today’s competitive electric utility marketplace, reliable and real-time information become the key factor for reliable delivery of power to the end-users, profitability of the electric utility and customer satisfaction. The operational and commercial demands of electric utilities require a high-performance data communication network that supports both existing functionalities and future operational requirements. In this respect, since such a communication network constitutes the core of the electric system automation applications, the design of a cost-effective and reliable network architecture is crucial. In this paper, the opportunities and challenges of a hybrid network architecture are discussed for electric system automation. More specifically, Internet based Virtual Private Networks, power line communications, satellite communications and wireless communications (wireless sensor networks, WiMAX and wireless mesh networks) are described in detail. The motivation of this paper is to provide a better understanding of the hybrid network architecture that can provide heterogeneous electric system automation application requirements. In this regard, our aim is to present a structured framework for electric utilities who plan to utilize new communication technologies for automation and hence, to make the decision making process more effective and direct.This work was supported by NEETRAC under Project #04-157

Optical wireless communication systems

The emerging field of optical wireless communication (OWC) systems is seen as potential complementary technology to the radio frequency wireless communications in certain applications. It is deemed as a possible technology in the future 5th Generation communication networks to address the spectrum congestion and improve the system's capacity. More research and developments in OWC is still needed in order for it to be adopted in current and future communication systems. This special issue brings together research papers on OWC covering free space optic, visible communications and ultraviolet communications

Power saving mechanism with less number of nodes in the routing path in Adhoc Wireless Networks using MARI Algorithm

Adhoc wireless networks have emerged as one of the key growth areas for wireless3 networking and computing technology. Adhoc networks are a new wireless networking paradigm for mobile hosts. Unlike traditional mobile wireless networks, adhoc networks do not rely on any fixed infrastructure. Instead, hosts rely on each other to keep the network connected. The nodes in ad-hoc networks are battery operated and have limited energy resources, which is indeed a key limitations. Each node consumes a large amount of energy while transmission or reception of packets, among the nodes. While the nodes depend on each other for efficient transferring of packets, it is a key issue in adhoc networks to have efficient methods for forwarding of packets between any given pair of nodes, with minimum power consumption and less number of intermediate nodes . In this study we propose an optimal routing protocol called MARI (Mobile Agent with Routing Intelligence). The MARI Topology proposed for power management is novel and is used for the consumption of minimum power in an adhoc wireless network, at each node. The Protocol groups the network into distinct networks with the selection of MARI nodes and Gateways for efficient packet transmission between any member node pair. The operational cycle at each node is classified into four distinct operations, i.e., transmitting, receiving, idle and sleep cycle, in order to achieve efficient power management in an Adhoc wireless network

Northern Sparks

An “episode of light” in Canada sparked by Expo 67 when new art forms, innovative technologies, and novel institutional and policy frameworks emerged together. Understanding how experimental art catalyzes technological innovation is often prized yet typically reduced to the magic formula of “creativity.” In Northern Sparks, Michael Century emphasizes the role of policy and institutions by showing how novel art forms and media technologies in Canada emerged during a period of political and social reinvention, starting in the 1960s with the energies unleashed by Expo 67. Debunking conventional wisdom, Century reclaims innovation from both its present-day devotees and detractors by revealing how experimental artists critically challenge as well as discover and extend the capacities of new technologies. Century offers a series of detailed cross-media case studies that illustrate the cross-fertilization of art, technology, and policy. These cases span animation, music, sound art and acoustic ecology, cybernetic cinema, interactive installation art, virtual reality, telecommunications art, software applications, and the emergent metadiscipline of human-computer interaction. They include Norman McLaren's “proto-computational” film animations; projects in which the computer itself became an agent, as in computer-aided musical composition and choreography; an ill-fated government foray into interactive networking, the videotext system Telidon; and the beginnings of virtual reality at the Banff Centre. Century shows how Canadian artists approached new media technologies as malleable creative materials, while Canada undertook a political reinvention alongside its centennial celebrations. Northern Sparks offers a uniquely nuanced account of innovation in art and technology illuminated by critical policy analysis

The Role of Physical Layer Security in Satellite-Based Networks

In the coming years, 6G will revolutionize the world with a large amount of bandwidth, high data rates, and extensive coverage in remote and rural areas. These goals can only be achieved by integrating terrestrial networks with non-terrestrial networks. On the other hand, these advancements are raising more concerns than other wireless links about malicious attacks on satellite-terrestrial links due to their openness. Over the years, physical layer security (PLS) has emerged as a good candidate to deal with security threats by exploring the randomness of wireless channels. In this direction, this paper reviews how PLS methods are implemented in satellite communications. Firstly, we discuss the ongoing research on satellite-based networks by highlighting the key points in the literature. Then, we revisit the research activities on PLS in satellite-based networks by categorizing the different system architectures. Finally, we highlight research directions and opportunities to leverage the PLS in future satellite-based networks