Energy conservation is crucial in wireless ad hoc sensor network design to increase network lifetime. Since communication consumes a major part of the energy used by a sensor node, efficient communication is important. Topology control aims at achieving more efficient communication by dropping links and reducing interference among simultaneous transmissions by adjusting the nodes’ transmission power. Since dropping links make a network more susceptible to node failure, a fundamental problem in wireless sensor networks is to find a communication graph with minimum interference and minimum power assignment aiming at an induced topology that can satisfy fault-tolerant properties. In this paper, we examine and propose linear integer programming formulations and a hybrid meta-heuristic GRASP/VNS (Greedy Randomized Adaptive Search Procedure/Variable Neighborhood Search) to determine the transmission power of each node while maintaining a fault-tolerant network and simultaneously minimize the interference and the total power consumption. Optimal biconnected topologies for moderately sized networks with minimum interference and minimum power are obtained using a commercial solver. We report computational simulations comparing the integer programming formulations and the GRASP/VNS, and evaluate the effectiveness of three meta-heuristics in terms of the tradeoffs between computation time and solution quality. We show that the proposed meta-heuristics are able to find good solutions for sensor networks with up to 400 nodes and that the GRASP/VNS was able to systematically find the best lower bounds and optimal solutions.
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Reliability is a constraint of low-power wireless connectivity, commonly addressed by the deployment of mesh topology. Accordingly, power consumption becomes a major concern during the design and implementation of such networks. Thus, a mono-objective optimization was implemented in this work to decrease the total amount of power consumed by a low-power wireless mesh network based on Thread protocol. Using a genetic algorithm, the optimization procedure takes into account a pre-defined connectivity matrix, in which the possible distances between all network devices are considered. The experimental proof-of-concept shows that a mean gain of 26.45 dB is achievable in a specific scenario. Through our experimental results, we conclude that the Thread mesh protocol has much leeway to meet the low-power consumption requirement of wireless sensor networks.
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This paper introduces a novel distributed algorithm designed to optimize the deployment of access points within Mobile Ad Hoc Networks (MANETs) for better service quality in infrastructure less environments. The algorithm operates based on local, independent execution by each network node, thus ensuring a high degree of scalability and adaptability to changing network conditions. The primary focus is to match the spatial distribution of access points with the distribution of client devices while maintaining strong connectivity to the network root. Using autonomous decision-making and choreographed path-planning, this algorithm bridges the gap between demand-responsive network service provision and the maintenance of crucial network connectivity links. The assessment of the performance of this approach is motivated by using numerical results generated by simulations.
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This paper discusses an Induction Generator (IG) system that provides regulated voltage at any load condition. It utilizes the classical self-excitation principle but, in addition to that, it makes use of a current regulated PWM inverter to control the output voltage magnitude. It is primarily intended for micro hydro plants to be used in rural areas, where the cost of conventional distribution system is high, and the water resources are available to drive an unregulated low hear turbine. The proposed topology is presented, followed by an analysis of the control structure. The methodology is validated via simulation studies.
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Bumping Elbows explores a workflow integrating 3D body scanning technology with robotic knitting to create personalized garments. Traditional 3D knitting development relies on 2D drafts and panels, rooted in industrial flatbed knitting practices. Our approach leverages accurate topology measurements from 3D body scans to directly inform garment design and production, allowing for custom fits to unique body shapes. We will demonstrate this process through live 3D scanning and software demonstrations, highlighting the challenges and opportunities integrating body scans and knitting techniques like goring. Our included software addresses limitations of previous work and outlines advancements needed for broader research adoption, emphasizing the potential of combining 3D scanning with robotic knitting. This method offers enhanced personalization and sustainability in garment production, showcasing the ongoing challenges and advancements in achieving precision in robotic knitting.
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This report is the final report for the FPGA accelerated PID controller, part of the Distributed Control Systems project. This project runs within the Lectoraat Robotics and High Tech Mechatronics of Fontys Hogeschool Engineering Eindhoven. The Lectoraat has the goal to develop applicable knowledge to support education and industry. This knowledge is acquired with projects run in conjunction with the industry. The report will go into detail for the software designed for this project, not the hardware design. This report is intended for follow up students working on the Distributed Control Systems project. Within this report the assumption is made that the reader is at least familiar with the terms EtherCAT, FPGA, Linux and PID controllers. However for each part a small basic introduction is included. For readers looking for the accomplishments in this project, the results are in chapter six. Following are short descriptions of the chapters in this report. The first chapter will give a short introduction to the project. It talks about why the project was conceived, where the project was done and what the expected end result is. The second chapter, the problem definition, talks about how the project has been defined, what is included and what is not and how the customer expects the final product to function and look like. The third chapter details the methodology used during this project. All the research preformed for this project will be described in the forth chapter. This chapter goes into the research into the Xilinx Zynq 7000 chip, Beckhoff's EtherCAT system, how the Serial Peripheral Interface works and how a PID controller functions. Following in chapter five the design is expanded upon. First the toolchain for building for the Zynq chip is explained. This is followed by and explanation of the different software parts that have been designed. Finally chapters six and seven provide the results and the conclusions and recommendations for this project.
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The additive manufacturing (AM) of high-quality products requires knowledge of the 3D-printing process and the related design guidelines. Allthough AM has been around for some years, many engineers still lack this knowledge. Therefore, Fontys University of Applied Sciences sets great store by training of engineers, education of engineering students and knowledge sharing on this topic. As an appetiser, this article offers a beginner’s course.
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This study focuses on the feasibility of electric aircraft operations between the Caribbean islands of Aruba, Bonaire, and Curaçao. It explores the technical characteristics of two different future electric aircraft types (i.e., Alice and ES-19) and compares their operational requirements with those of three conventional types currently in operation in the region. Flight operations are investigated from the standpoint of battery performance, capacity, and consumption, while their operational viability is verified. In addition, the CO2 emissions of electric operations are calculated based on the present energy mix, revealing moderate improvements. The payload and capacity are also studied, revealing a feasible transition to the new types. The impact of the local climate is discussed for several critical components, while the required legislation for safe operations is explored. Moreover, the maintenance requirements and costs of electric aircraft are explored per component, while charging infrastructure in the hub airport of Aruba is proposed and discussed. Overall, this study offers a thorough overview of the opportunities and challenges that electric aircraft operations can offer within the context of this specific islandic topology.
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Electrification of transportation, communication, working and living continues worldwide. Televisions, telephones, servers are an important part of everyday life. These loads and most sustainable sources as well, have one thing in common: Direct Current. The Dutch research and educational programme ‘DC – road to its full potential’ studies the impact of feeding these appliances from a DC grid. An improvement in energy efficiency is expected, other benefits are unknown and practical considerations are needed to come to a proper comparison with an AC grid. This paper starts with a brief introduction of the programme and its first stages. These stages encompass firstly the commissioning, selection and implementation of a safe and user friendly testing facility, to compare performance of domestic appliances when powered with AC and DC. Secondly, the relationship between the DC-testing facility and existing modeling and simulation assignments is explained. Thirdly, first results are discussed in a broad sense. An improved energy efficiency of 3% to 5% is already demonstrated for domestic appliances. That opens up questions for the performance of a domestic DC system as a whole. The paper then ends with proposed minor changes in the programme and guidelines for future projects. These changes encompass further studying of domestic appliances for product-development purposes, leaving less means for new and costly high-power testing facilities. Possible gains are 1) material and component savings 2) simpler and cheaper exteriors 3) stable and safe in-house infrastructure 4) whilst combined with local sustainable generation. That is the road ahead. 10.1109/DUE.2014.6827758
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The Smart Current Limiter is a switching DC to DC converter that provides a digitally pre-set input current control for inrush limiting and power management. Being able to digitally adjust the current level in combination with external feedback can be used for control systems like temperature control in high power DC appliances. Traditionally inrush current limiting is done using a passive resistance whose resistance changes depending on the current level. Bypassing this inrush limiting resister with a Mosfet improves efficiency and controllability, but footprint and losses remain large. A switched current mode controlled inrush limiter can limit inrush currents and even control the amount of current passing to the application. This enables power management and inrush current limitation in a single device. To reduce footprint and costs a balance between losses and cost-price on one side and electromagnetic interference on the other side is sought and an optimum switching frequency is chosen. To reduce cost and copper usage, switching happens on a high frequency of 300kHz. This increases the switching losses but greatly reduces the inductor size and cost compared to switching supplies running on lower frequencies. Additional filter circuits like snubbers are necessary to keep the control signals and therefore the output current stable.
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