11 research outputs found
Utilizing Magnetic Tunnel Junction Devices in Digital Systems
The research described in this dissertation is motivated by the desire to effectively utilize magnetic tunnel junctions (MTJs) in digital systems. We explore two aspects of this: (1) a read circuit useful for global clocking and magnetologic, and (2) hardware virtualization that utilizes the deeply-pipelined nature of magnetologic.
In the first aspect, a read circuit is used to sense the state of an MTJ (low or high resistance) and produce a logic output that represents this state. With global clocking, an external magnetic field combined with on-chip MTJs is used as an alternative mechanism for distributing the clock signal across the chip. With magnetologic, logic is evaluated with MTJs that must be sensed by a read circuit and used to drive downstream logic. For these two uses, we develop a resistance-to-voltage (R2V) read circuit to sense MTJ resistance and produce a logic voltage output. We design and fabricate a prototype test chip in the 3 metal 2 poly 0.5 um process for testing the R2V read circuit and experimentally validating its correctness. Using a clocked low/high resistor pair, we show that the read circuit can correctly detect the input resistance and produce the desired square wave output. The read circuit speed is measured to operate correctly up to 48 MHz. The input node is relatively insensitive to node capacitance and can handle up to 10s of pF of capacitance without changing the bandwidth of the circuit.
In the second aspect, hardware virtualization is a technique by which deeply-pipelined circuits that have feedback can be utilized. MTJs have the potential to act as state in a magnetologic circuit which may result in a deep pipeline. Streams of computation are then context switched into the hardware logic, allowing them to share hardware resources and more fully utilize the pipeline stages of the logic. While applicable to magnetologic using MTJs, virtualization is also applicable to traditional logic technologies like CMOS. Our investigation targets MTJs, FPGAs, and ASICs. We develop M/D/1 and M/G/1 queueing models of the performance of virtualized hardware with secondary memory using a fixed, hierarchical, round-robin schedule that predict average throughput, latency, and queue occupancy in the system. We develop three C-slow applications and calibrate them to a clock and resource model for FPGA and ASIC technologies. Last, using the M/G/1 model, we predict throughput, latency, and resource usage for MTJ, FPGA, and ASIC technologies. We show three design scenarios illustrating ways in which to use the model
Optimization of energy efficiency in data and WEB hosting centers
Mención Internacional en el tÃtulo de doctorThis thesis tackles the optimization of energy efficiency in data centers in terms of network
and server utilization.
For what concerns networking utilization the work focuses on Energy Efficient Ethernet
(EEE) - IEEE 802.3az standard - which is the energy-aware alternative to legacy Ethernet, and an
important component of current and future green data centers. More specifically the first contribution
of this thesis consists in deriving and analytical model of gigabit EEE links with coalescing
using M/G/1 queues with sleep and wake-up periods. Packet coalescing has been proposed to save
energy by extending the sojourn in the Low Power Idle state of EEE. The model presented in this
thesis approximates with a good accuracy both the energy saving and the average packet delay by
using a few significant traffic descriptors. While coalescing improves by far the energy efficiency
of EEE, it is still far from achieving energy consumption proportional to traffic. Moreover, coalescing
can introduce high delays. To this extend, by using sensitivity analysis the thesis evaluates
the impact of coalescing timers and buffer sizes, and sheds light on the delay incurred by adopting
coalescing schemes. Accordingly, the design and study of a first family of dynamic algorithms,
namely measurement-based coalescing control (MBCC), is proposed. MBCC schemes tune the
coalescing parameters on-the-fly, according to the instantaneous load and the coalescing delay
experienced by the packets. The thesis also discusses a second family of dynamic algorithms,
namely NT-policy coalescing control (NTCC), that adjusts the coalescing parameters based on
the sole occurrence of timeouts and buffer fill-ups. Furthermore, the performance of static as well
as dynamic coalescing schemes is investigated using real traffic traces. The results reported in this
work show that, by relying on run-time delay measurements, simple and practical MBCC adaptive
coalescing schemes outperform traditional static and dynamic coalescing while the adoption
of NTCC coalescing schemes has practically no advantages with respect to static coalescing when
delay guarantees have to be provided. Notably, MBCC schemes double the energy saving benefit
of legacy EEE coalescing and allow to control the coalescing delay.
For what concerns server utilization, the thesis presents an exhaustive empirical characterization
of the power requirements of multiple components of data center servers. The characterization
is the second key contribution of this thesis, and is achieved by devising different experiments
to stress server components, taking into account the multiple available CPU frequencies and the
presence of multicore servers. The described experiments, allow to measure energy consumption of server components and identify their optimal operational points. The study proves that the
curve defining the minimal CPU power utilization, as a function of the load expressed in Active
Cycles Per Second, is neither concave nor purely convex. Instead, it definitively shows a superlinear
dependence on the load. The results illustrate how to improve the efficiency of network
cards and disks. Finally, the accuracy of the model derived from the server components consumption
characterization is validated by comparing the real energy consumed by two Hadoop
applications - PageRank and WordCount - with the estimation from the model, obtaining errors
below 4:1%, on average.This work has been partially supported by IMDEA Networks Institute and the Greek State Scholarships
FoundationPrograma Oficial de Doctorado en IngenierÃa TelemáticaPresidente: Marco Giuseppe Ajmone Marsan.- Secretario: Jose Luis Ayala Rodrigo.- Vocal: Gianluca Antonio Rizz
Modelling, Dimensioning and Optimization of 5G Communication Networks, Resources and Services
This reprint aims to collect state-of-the-art research contributions that address challenges in the emerging 5G networks design, dimensioning and optimization. Designing, dimensioning and optimization of communication networks resources and services have been an inseparable part of telecom network development. The latter must convey a large volume of traffic, providing service to traffic streams with highly differentiated requirements in terms of bit-rate and service time, required quality of service and quality of experience parameters. Such a communication infrastructure presents many important challenges, such as the study of necessary multi-layer cooperation, new protocols, performance evaluation of different network parts, low layer network design, network management and security issues, and new technologies in general, which will be discussed in this book
Flexible Automation and Intelligent Manufacturing: The Human-Data-Technology Nexus
This is an open access book. It gathers the first volume of the proceedings of the 31st edition of the International Conference on Flexible Automation and Intelligent Manufacturing, FAIM 2022, held on June 19 – 23, 2022, in Detroit, Michigan, USA. Covering four thematic areas including Manufacturing Processes, Machine Tools, Manufacturing Systems, and Enabling Technologies, it reports on advanced manufacturing processes, and innovative materials for 3D printing, applications of machine learning, artificial intelligence and mixed reality in various production sectors, as well as important issues in human-robot collaboration, including methods for improving safety. Contributions also cover strategies to improve quality control, supply chain management and training in the manufacturing industry, and methods supporting circular supply chain and sustainable manufacturing. All in all, this book provides academicians, engineers and professionals with extensive information on both scientific and industrial advances in the converging fields of manufacturing, production, and automation
Flexible Automation and Intelligent Manufacturing: The Human-Data-Technology Nexus
This is an open access book. It gathers the first volume of the proceedings of the 31st edition of the International Conference on Flexible Automation and Intelligent Manufacturing, FAIM 2022, held on June 19 – 23, 2022, in Detroit, Michigan, USA. Covering four thematic areas including Manufacturing Processes, Machine Tools, Manufacturing Systems, and Enabling Technologies, it reports on advanced manufacturing processes, and innovative materials for 3D printing, applications of machine learning, artificial intelligence and mixed reality in various production sectors, as well as important issues in human-robot collaboration, including methods for improving safety. Contributions also cover strategies to improve quality control, supply chain management and training in the manufacturing industry, and methods supporting circular supply chain and sustainable manufacturing. All in all, this book provides academicians, engineers and professionals with extensive information on both scientific and industrial advances in the converging fields of manufacturing, production, and automation
Graduate course catalog (Florida International University). [2016-2017]
This catalog contains a description of the various policies, graduate programs, degree requirements, and course offerings at Florida International University during the 2016-2017 academic year.https://digitalcommons.fiu.edu/catalogs/1072/thumbnail.jp
Graduate course catalog (Florida International University). [2011-2012]
This catalog contains a description of the various policies, graduate programs, degree requirements, and course offerings at Florida International University during the 2011-2012 academic year.https://digitalcommons.fiu.edu/catalogs/1064/thumbnail.jp
Graduate course catalog (Florida International University). [2015-2016]
This catalog contains a description of the various policies, graduate programs, degree requirements, and course offerings at Florida International University during the 2015-2016 academic year.https://digitalcommons.fiu.edu/catalogs/1067/thumbnail.jp