1,287 research outputs found

    High-performance hardware accelerators for image processing in space applications

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    Mars is a hard place to reach. While there have been many notable success stories in getting probes to the Red Planet, the historical record is full of bad news. The success rate for actually landing on the Martian surface is even worse, roughly 30%. This low success rate must be mainly credited to the Mars environment characteristics. In the Mars atmosphere strong winds frequently breath. This phenomena usually modifies the lander descending trajectory diverging it from the target one. Moreover, the Mars surface is not the best place where performing a safe land. It is pitched by many and close craters and huge stones, and characterized by huge mountains and hills (e.g., Olympus Mons is 648 km in diameter and 27 km tall). For these reasons a mission failure due to a landing in huge craters, on big stones or on part of the surface characterized by a high slope is highly probable. In the last years, all space agencies have increased their research efforts in order to enhance the success rate of Mars missions. In particular, the two hottest research topics are: the active debris removal and the guided landing on Mars. The former aims at finding new methods to remove space debris exploiting unmanned spacecrafts. These must be able to autonomously: detect a debris, analyses it, in order to extract its characteristics in terms of weight, speed and dimension, and, eventually, rendezvous with it. In order to perform these tasks, the spacecraft must have high vision capabilities. In other words, it must be able to take pictures and process them with very complex image processing algorithms in order to detect, track and analyse the debris. The latter aims at increasing the landing point precision (i.e., landing ellipse) on Mars. Future space-missions will increasingly adopt Video Based Navigation systems to assist the entry, descent and landing (EDL) phase of space modules (e.g., spacecrafts), enhancing the precision of automatic EDL navigation systems. For instance, recent space exploration missions, e.g., Spirity, Oppurtunity, and Curiosity, made use of an EDL procedure aiming at following a fixed and precomputed descending trajectory to reach a precise landing point. This approach guarantees a maximum landing point precision of 20 km. By comparing this data with the Mars environment characteristics, it is possible to understand how the mission failure probability still remains really high. A very challenging problem is to design an autonomous-guided EDL system able to even more reduce the landing ellipse, guaranteeing to avoid the landing in dangerous area of Mars surface (e.g., huge craters or big stones) that could lead to the mission failure. The autonomous behaviour of the system is mandatory since a manual driven approach is not feasible due to the distance between Earth and Mars. Since this distance varies from 56 to 100 million of km approximately due to the orbit eccentricity, even if a signal transmission at the light speed could be possible, in the best case the transmission time would be around 31 minutes, exceeding so the overall duration of the EDL phase. In both applications, algorithms must guarantee self-adaptability to the environmental conditions. Since the Mars (and in general the space) harsh conditions are difficult to be predicted at design time, these algorithms must be able to automatically tune the internal parameters depending on the current conditions. Moreover, real-time performances are another key factor. Since a software implementation of these computational intensive tasks cannot reach the required performances, these algorithms must be accelerated via hardware. For this reasons, this thesis presents my research work done on advanced image processing algorithms for space applications and the associated hardware accelerators. My research activity has been focused on both the algorithm and their hardware implementations. Concerning the first aspect, I mainly focused my research effort to integrate self-adaptability features in the existing algorithms. While concerning the second, I studied and validated a methodology to efficiently develop, verify and validate hardware components aimed at accelerating video-based applications. This approach allowed me to develop and test high performance hardware accelerators that strongly overcome the performances of the actual state-of-the-art implementations. The thesis is organized in four main chapters. Chapter 2 starts with a brief introduction about the story of digital image processing. The main content of this chapter is the description of space missions in which digital image processing has a key role. A major effort has been spent on the missions in which my research activity has a substantial impact. In particular, for these missions, this chapter deeply analizes and evaluates the state-of-the-art approaches and algorithms. Chapter 3 analyzes and compares the two technologies used to implement high performances hardware accelerators, i.e., Application Specific Integrated Circuits (ASICs) and Field Programmable Gate Arrays (FPGAs). Thanks to this information the reader may understand the main reasons behind the decision of space agencies to exploit FPGAs instead of ASICs for high-performance hardware accelerators in space missions, even if FPGAs are more sensible to Single Event Upsets (i.e., transient error induced on hardware component by alpha particles and solar radiation in space). Moreover, this chapter deeply describes the three available space-grade FPGA technologies (i.e., One-time Programmable, Flash-based, and SRAM-based), and the main fault-mitigation techniques against SEUs that are mandatory for employing space-grade FPGAs in actual missions. Chapter 4 describes one of the main contribution of my research work: a library of high-performance hardware accelerators for image processing in space applications. The basic idea behind this library is to offer to designers a set of validated hardware components able to strongly speed up the basic image processing operations commonly used in an image processing chain. In other words, these components can be directly used as elementary building blocks to easily create a complex image processing system, without wasting time in the debug and validation phase. This library groups the proposed hardware accelerators in IP-core families. The components contained in a same family share the same provided functionality and input/output interface. This harmonization in the I/O interface enables to substitute, inside a complex image processing system, components of the same family without requiring modifications to the system communication infrastructure. In addition to the analysis of the internal architecture of the proposed components, another important aspect of this chapter is the methodology used to develop, verify and validate the proposed high performance image processing hardware accelerators. This methodology involves the usage of different programming and hardware description languages in order to support the designer from the algorithm modelling up to the hardware implementation and validation. Chapter 5 presents the proposed complex image processing systems. In particular, it exploits a set of actual case studies, associated with the most recent space agency needs, to show how the hardware accelerator components can be assembled to build a complex image processing system. In addition to the hardware accelerators contained in the library, the described complex system embeds innovative ad-hoc hardware components and software routines able to provide high performance and self-adaptable image processing functionalities. To prove the benefits of the proposed methodology, each case study is concluded with a comparison with the current state-of-the-art implementations, highlighting the benefits in terms of performances and self-adaptability to the environmental conditions

    Interconnect design for the edge computing system-on-chip

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    Nowadays the majority of system-on-chips are designed by placing various IP blocks such as CPUs, memories and accelerators on the same chip. With the advantage of silicon manufacturing technologies, it has become possible to place hundreds of CPU cores and other design blocks on the same chip. A communication system that transfers data between chip components largely affects overall chip performance, computational speed and response time for external events. Firstly, this thesis studies the main on-chip interconnect design paradigms. According to the presented research, various architectures may be chosen for an interconnect design depending on the required complexity and number of subsystems. The shared and hybrid bus interconnects are one of the oldest means of on-chip communication. They are efficient for small systems with no more than ten IP blocks. The crossbars or bus matrix interconnects can help to build on-chip communication systems which can efficiently interconnect dozens of system-on-chip modules. The networks-on-chip can provide a communication solution for large scale chip designs with hundreds of IP blocks. The second part of this thesis focuses on the novel Ballast chip implementation and its interconnect design. The Ballast is a heterogeneous multiprocessor chip designed for edge computing and general-purpose computing applications. In this thesis Ballast interconnect was designed from scratch by using a cascaded crossbar approach by connecting three open-sourced AXI protocol bus matrices. The designed interconnect allows to efficiently connect 6 bus masters with 9 slaves and provides up to 9,6 GB/s bandwidth for the most productive CPU subsystem

    Survivability stategies in all optical networks.

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    Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, 2006.Thesis (M.Sc.)-University of KwaZulu-Natal, 2006.Recent advances in fiber optics technology have enabled extremely high-speed transport of different forms of data, on multiple wavelengths of an optical fiber, using Dense Wavelength Division Multiplexing (DWDM). It has now become possible to deploy high-speed, multi-service networks using DWDM technology. As the amount of traffic carried has increased, any single failure can be catastrophic. Survivability becomes indispensable in such networks. Therefore, it is imperative to design networks that can quickly and efficiently recover from failures. Most research to date in survivable optical network design and operation focuses on single link failures, however, the occurrence of multiple-link failures are not uncommon in networks today. Multi-link failure scenarios can arise out of two common situations. First, an arbitrary link may fail in the network, and before that link can be repaired, another link fails, thus creating a multi-link failure sequence. Secondly, it might happen in practice that two distinct physical links may be routed via the same common duct or physical channel. A failure at that shared physical location creates a logical multiple-link failure. In this dissertation, we conduct an intensive study of mechanisms for achieving survivability in optical networks. From the many mechanisms presented in the literature the focus of this work was on protection as a mechanism of survivability. In particular four protection schemes were simulated and their results analyzed to ascertain which protection scheme achieves the best survivability in terms of number of wavelengths recovered for a specific failure scenario. A model network was chosen and the protection schemes were evaluated for both single and multiple link and node failures. As an indicator of the performance of these protection schemes over a period of time average service availability and average loss in traffic for each protection scheme was also simulated. Further simulations were conducted to observe the percentage link and node utilization of each scheme hence allowing us to determine the strain each protection scheme places on network resources when traffic in the network increases. Finally based on these simulation results, recommendations of which protection scheme and under what failure conditions they should be used are made.Recent advances in fiber optics technology have enabled extremely high-speed transpor

    Publications of the Jet Propulsion Laboratory - July through December 1970

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    Bibliography of technical literature resulting from aerospace research and development at Jet Propulsion Laboratorie

    Advanced Information Systems and Technologies

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    This book comprises the proceedings of the VI International Scientific Conference “Advanced Information Systems and Technologies, AIST-2018”. The proceeding papers cover issues related to system analysis and modeling, project management, information system engineering, intelligent data processing, computer networking and telecomunications, modern methods and information technologies of sustainable development. They will be useful for students, graduate students, researchers who interested in computer science

    The STAR MAPS-based PiXeL detector

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    The PiXeL detector (PXL) for the Heavy Flavor Tracker (HFT) of the STAR experiment at RHIC is the first application of the state-of-the-art thin Monolithic Active Pixel Sensors (MAPS) technology in a collider environment. Custom built pixel sensors, their readout electronics and the detector mechanical structure are described in detail. Selected detector design aspects and production steps are presented. The detector operations during the three years of data taking (2014-2016) and the overall performance exceeding the design specifications are discussed in the conclusive sections of this paper

    JPL Quarterly Technical Review, Volume 2, No. 1, April 1972

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    Mariner spacecraft equipment, propulsion systems, telemetry, and spacecraft trackin

    Approach to C2F2C (customer to factory to customer) strategy: a case study of the Fanqing Furniture Company

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    Hotel furniture manufacturers, as key components of modern service industry, have become leading service companies concerning China's economic development. Consumer-driven business model and mass customization are becoming important direction of hotel furniture manufacturers’ transformation and upgrade. In a context of fragmented competition and individualized customers’ demand, it is difficult to take advantage of the low cost and high efficiency of mass production, while meeting the customers’ individualized needs. Internet led business increases the difficulty of balancing the offer of large production and customization, because companies face a high cost (Customer to Factory), while the customers’ satisfaction is low (Factory to Customer). Finding a solution to this trade-off is not only a major challenge in the process of company model transformation, but also an important topic that has not yet been studied in depth. Based on Fanqing Hotel Furniture Company’s empirical case of solving the contradiction between individualized demand and mass production, this thesis studies the evolution of hotel furniture manufacturers’ (HFM) innovation ecosystem and the value co-creation mode. The C2F2C (Customer to Factory to Customer) strategy of Fanqing was constructed based on both company innovation ecosystem theory and customer value co-creation theory. By implementing the C2F2C strategy, Fanqing has realized standardization, informatization and lean production, and also fulfilled customers’ needs and improved their satisfaction. The C2F2C strategy also helps to reduce costs and achieve value co-creation between the company and customers. This thesis explores an effective way to improve technological innovation ability and international competitiveness of HFM in China.As empresas de móveis para hotéis constituem um sector importante no desenvolvimento da indústria de serviços modernos, liderando já a indústria no desenvolvimento económico da China. Seguir um modelo de negócio de personalização em larga escala e orientação para o consumidor aponta ser uma direção significativa a tomar para a transformação e inovação das empresas de serviços. Face à concorrência individualizada e fragmentada na procura de clientes da indústria hoteleira, é difícil oferecer ao cliente uma personalização em larga escala, que permita atingir as vantagens de baixo custo e alta eficiência de produção em volume, atendendo simultaneamente à personalização das necessidades de cada cliente. Na comercialização pela internet é mais difícil equilibrar a oferta de uma produção em larga escala e personalizada, porque é elevado o custo em C2F, mas em contrapartida baixo o nível de satisfação do cliente em F2C. Como suporte empírico, esta tese analisou o caso da empresa de Móveis para Hotéis Fanqing, que resolveu a contradição entre procura individualizada e produção de massa em grande escala, permitindo estudar a evolução para um ecossistema inovador e de criação conjunta de valor entre empresas de móveis e clientes nesta industria de mobiliário para hóteis (HFM). A estratégia da relação cliente para fabricante e deste para cliente (C2F2C) da Fanqing foi desenvolvida com base nas teorias da inovação do ecossistema e da criação de valor conjunta. Ao implementar a estratégia de C2F2C, a Fanqing operou tanto a standardização, a informatização e a produção lean, como a satisfação do cliente preenchendo as suas necessidades. A estratégia C2F2C permite reduzir custos e potencia a criação conjunta de valor entre fabricantes e clientes, explorando uma maneira eficaz de melhorar a capacidade de inovação tecnológica e a competitividade internacional das empresas de móveis para hotéis da China

    Bibliography of Lewis Research Center Technical Publications announced in 1991

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    This compilation of abstracts describes and indexes the technical reporting that resulted from the scientific engineering work performed and managed by the Lewis Research Center in 1991. All the publications were announced in the 1991 issues of STAR (Scientific and Technical Aerospace Reports) and/or IAA (International Aerospace Abstracts). Included are research reports, journal articles, conference presentations, patents and patent applications, and theses
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