Computer Architectures to Close the Loop in Real-time Optimization

© 2015 IEEE.Many modern control, automation, signal processing and machine learning applications rely on solving a sequence of optimization problems, which are updated with measurements of a real system that evolves in time. The solutions of each of these optimization problems are then used to make decisions, which may be followed by changing some parameters of the physical system, thereby resulting in a feedback loop between the computing and the physical system. Real-time optimization is not the same as fast optimization, due to the fact that the computation is affected by an uncertain system that evolves in time. The suitability of a design should therefore not be judged from the optimality of a single optimization problem, but based on the evolution of the entire cyber-physical system. The algorithms and hardware used for solving a single optimization problem in the office might therefore be far from ideal when solving a sequence of real-time optimization problems. Instead of there being a single, optimal design, one has to trade-off a number of objectives, including performance, robustness, energy usage, size and cost. We therefore provide here a tutorial introduction to some of the questions and implementation issues that arise in real-time optimization applications. We will concentrate on some of the decisions that have to be made when designing the computing architecture and algorithm and argue that the choice of one informs the other

English for Study and Work

Подано всі види діяльності студентів з вивчення англійської мови, спрямовані на розвиток мовної поведінки, необхідної для ефективного спілкування в академічному та професійному середовищах. Містить завдання і ситуації, типові для різноманітних академічних та професійних сфер. Структура організації змісту – модульна, охоплює певні мовленнєві вміння залежно від мовної поведінки. Даний модуль має на меті розвиток у студентів умінь і навичок академічного і професійно- орієнтованого мовлення, необхідних для участі в дискусіях, семінарах, конференціях та при підготовці й проведенні презентацій (виступів-доповідей). Зразки текстів – автентичні, містять цікаву та актуальну інформацію з загальнонаукової та професійної тематики. Ресурси для самостійної роботи (Частина ІІ) містять завдання та вправи для розвитку словникового запасу та розширення діапазону функціональних зразків, необхідних для виконання певних функцій, та завдання, які спрямовані на організацію самостійної роботи студентів. За допомогою засобів діагностики студенти можуть самостійно перевірити засвоєння навчального матеріалу та оцінити свої досягнення. Наводяться граматичні явища і вправи для їх засвоєння. Призначений для студентів технічних університетів гірничого профілю. Може використовуватися для викладання вибіркових курсів з англійської мови, а також для самостійного вивчення англійської мови викладачами, фахівцями і науковцями різних інженерних галузей

Efficient Neuromorphic Computing Enabled by Spin-Transfer Torque: Devices, Circuits and Systems

Present day computers expend orders of magnitude more computational resources to perform various cognitive and perception related tasks that humans routinely perform everyday. This has recently resulted in a seismic shift in the field of computation where research efforts are being directed to develop a neurocomputer that attempts to mimic the human brain by nanoelectronic components and thereby harness its efficiency in recognition problems. Bridging the gap between neuroscience and nanoelectronics, this thesis demonstrates the encoding of biological neural and synaptic functionalities in the underlying physics of electron spin. Description of various spin-transfer torque mechanisms that can be potentially utilized for realizing neuro-mimetic device structures is provided. A cross-layer perspective extending from the device to the circuit and system level is presented to envision the design of an All-Spin neuromorphic processor enabled with on-chip learning functionalities. Device-circuit-algorithm co-simulation framework calibrated to experimental results suggest that such All-Spin neuromorphic systems can potentially achieve almost two orders of magnitude energy improvement in comparison to state-of-the-art CMOS implementations

Mobiililaitteiden hienojakoinen energiaprofilointi

Mobile phones have several use cases such as making a phone call, sending an SMS, browsing the Internet, or playing a game. Mobile phones are also equipped with a wide variety of hardware allowing these activities. The overall energy consumption is easily measurable but it does not explain how much power is dissipated on particular activities and which devices are mostly responsible for the consumption. Thus, this thesis defines the concept of fine-grained energy profiling where the total energy consumed is broken down into subsystems. This thesis examines mobile phone power dissipation and energy consumption analysis. It describes how to measure overall total energy consumed by the device and develops methods that allow breaking down the energy consumption to components or subsystems. Specifically, the tools developed in this thesis allow studying the energy consumed by the CPU, GPU, display, WiFi, Cellular 3G and SSD disk. The device studied here is the Nokia N900 Maemo/Linux phone. This thesis describes a full-system power measurement setup including a fake battery and DAQ acting as an electric power meter. The thesis also develops logging tools that monitor the subsystem load and provide a method for formulating a linear regression model between these two through a set of microbenchmarks. This model allows estimating the subsystem energy consumption and total energy consumption based on observed loads of the subsystems. The model achieved 80% accuracy when compared with measured total energy consumption to the total power dissipation predicted by model.Matkapuhelimia voi käyttää moniin tarkoituksiin kuten puheluihin, tekstiviestien lähettämiseen, Internet-selailuun tai pelien pelaamiseen. Tämän mahdollistamiseksi nykyaikaisissa matkapuhelimissa on paljon erilaisia laitteistokomponentteja eli alijärjestelmiä. Matkapuhelimen kokonaisvirrankulutus on helppo mitata, mutta se ei selitä sitä, kuinka paljon kukin alijärjestelmä kuluttaa energiaa. Tämän ongelman ratkaisemiseksi tässä työssä määritellään hienojakoisen energiaprofiloinnin käsite, jonka avulla kokonaisenergiankulutus voidaan jakaa alijärjestelmien energiankulutukseksi. Tässä työssä tutkitaan matkapuhelimen tehon ja energiankulutuksen analysointia. Työssä kehitetään menetelmä matkapuhelimen kokonaisenergiankulutuksen mittaamiseen. Lisäksi esitellään menetelmä, jonka avulla energiankulutus jyvitetään matkapuhelimen alijärjestelmille. Työssä jyvitys tehdään seuraaville alijärjestelmille: suoritin (CPU), grafiikkasuoritin (GPU), näyttö, langaton verkko (WiFi), mobiilidatayhteys (3G) sekä tallennuslevy (SSD). Laitteena käytettiin Nokia N900 Maemo/Linux -puhelinta. Työssä esitellään kokonaisenergiankulutuksen mittausjärjestely, joka sisältää valeakun ja virrankulutusmittarina toimivan DAQ-laitteen. Lisäksi työssä kehitetään työkalu, jonka avulla matkapuhelimen alijärjestelmien käyttöastetta voidaan tarkkailla ja tallentaa. Lopuksi työssä esitellään lineaariseen regressioon perustuva mallinnus, joka mahdollistaa mitatun tehon ja kokonaisenergiankulutuksen jyvittämisen yksittäisille alijärjestelmäkomponenteille. Työssä kehitetty malli saavutti noin 80 % selitysasteen, kun mallin ennustamaa tehonkulutusta verrattiin mitattuun tehonkulutukseen

The Umbrella File System: Storage Management Across Heterogeneous Devices

With the advent of Flash based solid state devices (SSDs), the differences in physical devices used to store data in computers are becoming more and more pronounced. Effectively mapping the differences in storage devices to the files, and applications using the devices, is the problem addressed in this dissertation. This dissertation presents the Umbrella File System (UmbrellaFS), a layered file system designed to effectively map file and device level differences, while maintaining a single coherent directory structure for users. Particular files are directed to appropriate underlying file systems by intercepting system calls connecting the Virtual File System (VFS) to the underlying file systems. Files are evaluated by a policy module that can examine both filenames and file metadata to make decisions about final placement. Files are transparently directed to and moved between appropriate file systems based on their characteristics. A prototype of UmbrellaFS is implemented as a loadable kernel module in the 2.4 and 2.6 Linux kernels. In addition to providing the ability to direct files to file systems, UmbrellaFS enables different decisions at other layers of the storage stack. In particular, alternate page cache writeback methods are presented through the use of UmbrellaFS. A multiple queue strategy based on file sequentiality and a sorting strategy are presented as alternatives to standard Linux cache writeback protocols. These strategies are implemented in a 2.6 Linux kernel and show improvements in a variety of benchmarks and tests

Performance Optimization of Memory Intensive Applications on FPGA Accelerator

L'abstract è presente nell'allegato / the abstract is in the attachmen