20 research outputs found
Adaptive AT2 Optimal Algorithms on reconfigurable meshes
Recently a few self-simulation algorithms have been developed to execute algorithms on a reconfigurable mesh (RM) of size smaller than recommended in those algorithms. Optimal slowdown, in self-simulation, has been achieved with the compromise that the resultant algorithms fail to remain AT2 optimal. In this paper we have introduced, for the first time, the idea of adaptive algorithm which runs on RM of variable sizes without compromising the AT2 optimality. We have supported our idea by developing adaptive algorithms, for sorting items and computing the contour of maximal elements of a set of planar points on RM. We have also conjectured that to obtain an AT2 algorithm to solve a problem of size n with I(n) information content on an RM of size p x q where pq=kI(n), it is sufficient to form buses of length O (k)
An automated apparatus for non-contact inspecting of mass produced custom products.
Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2009.The evolution of the manufacturing industry may be viewed as proceeding from Dedicated
Manufacturing Systems (DMS) to Reconfigurable Manufacturing Systems (RMS). Customer
requirements change unpredictably, and so DMS are no longer able to meet modern
manufacturing requirements. RMS are designed with the focus of providing rapid response to a
change in product design, within specified part families. The movement from DMS to RMS
facilitates mass-production of custom products. Custom parts require inspection routines that can
facilitate variations in product parameters such as dimensions, shape, and throughputs. Quality
control and part inspection are key processes in the lifecycle of a product. These processes are
able to verify product quality; and can provide essential feedback for enhancing other processes.
Mass-producing custom parts requires more complex and frequent quality control and inspection
routines, than were implemented previously. Complex, and higher frequencies of inspection
negatively impact inspection times, and inherently, production rates. For manufacturers to
successfully mass-produce custom parts, processes which can perform complex and varying
quality control operations need to be employed. Furthermore, such processes should perform
inspections without significantly impacting production rates. A method of reducing the impact
of high frequency inspection of customized parts on production rates is needed.
This dissertation focuses on the research, design, construction, assembly, and testing of a Non-
Contact Automated Inspection System (NCAIS). The NCAIS was focused on performing quality
control operations whilst maintaining the maximum production rate of a particular Computer
Integrated Manufacturing (CIM) cell. The CIM cell formed part of a research project in the
School of Mechanical Engineering, University of KwaZulu-Natal; and was used to simulate
mass-production of custom parts. Two methods of maintaining the maximum production rate
were explored. The first method was the automated visual inspection of moving custom parts.
The second method was to inspect only specified Regions of Interest (ROIs). Mechatronic
engineering principles were used to integrate sensor articulation, image acquisition, and image
processing systems. A specified maximum production rate was maintained during inspection,
without stoppage of parts along the production line occurring. The results obtained may be
expanded to specific manufacturing industries
Contemporary Robotics
This book book is a collection of 18 chapters written by internationally recognized experts and well-known professionals of the field. Chapters contribute to diverse facets of contemporary robotics and autonomous systems. The volume is organized in four thematic parts according to the main subjects, regarding the recent advances in the contemporary robotics. The first thematic topics of the book are devoted to the theoretical issues. This includes development of algorithms for automatic trajectory generation using redudancy resolution scheme, intelligent algorithms for robotic grasping, modelling approach for reactive mode handling of flexible manufacturing and design of an advanced controller for robot manipulators. The second part of the book deals with different aspects of robot calibration and sensing. This includes a geometric and treshold calibration of a multiple robotic line-vision system, robot-based inline 2D/3D quality monitoring using picture-giving and laser triangulation, and a study on prospective polymer composite materials for flexible tactile sensors. The third part addresses issues of mobile robots and multi-agent systems, including SLAM of mobile robots based on fusion of odometry and visual data, configuration of a localization system by a team of mobile robots, development of generic real-time motion controller for differential mobile robots, control of fuel cells of mobile robots, modelling of omni-directional wheeled-based robots, building of hunter- hybrid tracking environment, as well as design of a cooperative control in distributed population-based multi-agent approach. The fourth part presents recent approaches and results in humanoid and bioinspirative robotics. It deals with design of adaptive control of anthropomorphic biped gait, building of dynamic-based simulation for humanoid robot walking, building controller for perceptual motor control dynamics of humans and biomimetic approach to control mechatronic structure using smart materials
Aeronautical engineering: A continuing bibliography with indexes (supplement 270)
This bibliography lists 600 reports, articles, and other documents introduced into the NASA scientific and technical information system in September, 1991. Subject coverage includes: design, construction and testing of aircraft and aircraft engines; aircraft components, equipment and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics
Multiphysics Simulation and Model-based System Testing of Automotive E-Powertrains
Programa Oficial de Doutoramento en Enxe帽ar铆a Naval e Industrial . 5015V01[Abstract]
Model-Based System Testing emerges as a new paradigm for the development
cycle that is currently gaining momentum, especially in the automotive industry.
This novel approach is focused on combining computer simulation and real experimentation
to shift the bulk of problem detection and redesign tasks towards the
early stages of the developments. Along these lines, Model-Based System Testing
is aimed at decreasing the amount of resources invested in these tasks and enabling
the early identification of design flaws and operation problems before a full-vehicle
prototype is available. The use of Model-Based System Testing, however, requires to
implement some critical technologies, three of which will be discussed in this thesis.
The first task addressed in this thesis is the design of a multiplatform framework
to assess the description and resolution of the equations of motion of virtual
models used in simulation. This framework enables the efficiency evaluation of different
modelling and solution methods and implementations. In Model-Based System
Testing contexts virtual models interact with physical components, therefore it is
mandatory to guarantee their real-time capabilities, regardless of the software or
hardware implementations.
Second, estimation techniques based on Kalman Filters are of interest in Model-
Based System Testing applications to evaluate parameters, inputs or states of a
virtual model of a given system. These procedures can be combined with the use
of Digital Twins, virtual counterparts of real systems, with which they exchange
information in a two-way communication. The available measurements from the
sensors located at a physical system can be fused with the results obtained from
the simulation of the virtual model. Thus, this avenue improves the knowledge of
the magnitudes that cannot be measured directly by these sensors. In turn, the
outcomes obtained from the simulation of the virtual model could serve to make
decisions and apply corrective actions onto the physical system.
Third, co-simulation techniques are necessary when a system is split into several
subsystems that are coordinated through the exchange of a reduced set of variables
at discrete points in time. This is the case with a majority of Model-Based System
Testing applications, in which physical and virtual components are coupled through
a discrete-time communication gateway. The resulting cyber-physical applications
are essentially an example of real-time co-simulation, in which all the subsystems
need to achieve real-time performance. Due to the presence of physical components,
which cannot iterate over their integration steps, explicit schemes are often
mandatory. These, however, introduce errors associated with the inherent delays of
a discrete communication interface. These errors can render co-simulation results
inaccurate and even unstable unless they are eliminated. This thesis will address
this correction by means of an energy-based procedure that considers the power
exchange between subsystems.
This research work concludes with an example of a cyber-physical application,
in which real components are interfaced to a virtual environment, which requires
the application of all the MBST technologies addressed in this thesis.[Resumen]
Los ensayos de sistemas basados en modelos emergen como un nuevo paradigma
de desarrollo que actualmente est谩 ganando popularidad, especialmente en la industria
automotriz. Este nuevo enfoque se centra en combinar la simulaci贸n por
ordenador con la experimentaci贸n para desplazar la mayor parte de la detecci贸n
de problemas y redise帽os hacia las fases tempranas del desarrollo. De esta forma,
los ensayos de sistemas basados en modelos se centran en disminuir la cantidad de
recursos invertidos en estas tareas y habilitar la identificaci贸n temprana de errores
de dise帽o y problemas durante la operaci贸n, incluso antes de que los prototipos del
veh铆culo completo est茅n disponibles. Sin embargo, el uso de esta estrategia requiere
implementar algunas tecnolog铆as cr铆ticas, tres de las cuales ser谩n tratadas en esta
tesis.
La primera tarea abordada en esta tesis es el dise帽o de un entorno multiplataforma
para evaluar la descripci贸n y resoluci贸n de las ecuaciones de la din谩mica
de los modelos virtuales usados en las simulaciones. Este marco permite una evaluaci贸n
eficiente de las diferentes formas de modelar los sistemas y de los m茅todos
de resoluci贸n e implementaci贸n. En este contexto de ensayos basados en modelos,
los sistemas virtuales interact煤an con los componentes de los sistemas f铆sicos,
por lo tanto es necesario garantizar sus capacidades de ejecuci贸n en tiempo real,
independientemente de la plataforma de software y hardware utilizada.
En segundo lugar, las t茅cnicas de estimaci贸n basadas en filtros de Kalman son de
gran inter茅s en las aplicaciones que usan ensayos basados en modelos para evaluar
los par谩metros, entradas o estados de los modelos virtuales de un sistema dado. Estos
procedimientos se pueden combinar con el uso de gemelos digitales, hom贸logos
virtuales de un sistema f铆sico, con el cual mantienen un flujo bidireccional de intercambio
de informaci贸n. Las medidas disponibles procedentes de los sensores
instalados en un sistema f铆sico se pueden combinar con los resultados obtenidos de
la simulaci贸n del sistema virtual. De este modo, este enfoque mejora el conocimiento
de las magnitudes que no pueden ser medidas directamente por los sensores. A su
vez, los resultados de la simulaci贸n de los sistemas de los modelos virtuales pueden
servir para tomar decisiones y aplicar medidas correctivas al sistema real.
En tercer lugar, las t茅cnicas de co-simulaci贸n son necesarias cuando un sistema
se divide en varios subsistemas, coordinados a trav茅s del intercambio de un reducido
n煤mero de variables en momentos puntuales. Este es el caso de la mayor parte de
las aplicaciones que siguen la estrategia de ensayos basados en modelos, en los cuales
los componentes f铆sicos y virtuales se acoplan mediante una comunicaci贸n en tiempo
discreto. Como resultado las aplicaciones ciberf铆sicas son en esencia un ejemplo de
co-simulaci贸n en tiempo real, en la que todos los subsistemas necesitan cumplir los
requisitos de ejecuci贸n en tiempo real. Debido a la presencia de componentes f铆sicos,
que no pueden reiterar sus pasos de integraci贸n, el uso de esquemas expl铆citos es
frecuentemente necesario. Sin embargo, estos esquemas introducen errores asociados
con los retrasos propios de una interfaz de tiempo discreto. Estos errores pueden
dar lugar a resultados err贸neos e incluso inestabilizar la co-simulaci贸n, si no son
eliminados. Esta tesis aborda la correcci贸n de la co-simulaci贸n a trav茅s de m茅todos
energ茅ticos basados en la potencia intercambiada por los subsistemas. Este trabajo de investigaci贸n concluye con un ejemplo de aplicaci贸n ciberf铆sica,
en la que se conectan componentes reales a una simulaci贸n por ordenador. Esta
aplicaci贸n requiere la aplicaci贸n de las tecnolog铆as de ensayos basados en modelos
presentadas a lo largo de esta tesis.[Resumo]
Os ensaios de sistemas baseados en modelos xorden como un novo paradigma
de desenvolvemento que actualmente est谩 ga帽ando popularidade, especialmente na
industria automotriz. Este novo enfoque c茅ntrase en combinar a simulaci贸n por
ordenador coa experimentaci贸n para desprazar a maior parte da detecci贸n de problemas
e redese帽os cara as fases iniciais do ciclo de produto. Deste xeito, os ensaios
de sistemas baseados en modelos fundam茅ntanse en diminu铆r a cantidade de recursos
investidos nestas tarefas e habilitar a identificaci贸n temper谩 de erros de dese帽o
e problemas durante a operaci贸n, a铆nda se os prototipos do veh铆culo completo non
est谩n dispo帽ibeis. Por茅n, o uso desta estratexia require implementar algunhas tecnolox铆as cr铆icas, tres das cales ser谩n tratadas nesta tese.
A primeira tarefa tratada nesta tese 茅 o dese帽o dun entorno multiplataforma
para avaliar a descripci贸n e resoluci贸n das ecuaci贸ns da din谩mica dos modelos virtuais
empregados nas simulaci贸ns. Este entorno permite unha avaluaci贸n eficiente
dos diferentes xeitos de modelar os sistemas e dos m茅todos de resoluci贸n e implementaci贸n. Neste contexto de ensaios baseados en modelos, os sistemas virtuais
interact煤an cos compo帽entes dos sistemas f铆sicos, polo tanto 茅 necesario garantir as
s煤as capacidades de execuci贸n en tempo real, independentemente da plataforma de
hardware e software escollida.
En segundo lugar, as t茅cnicas de estimaci贸n baseadas en filtros de Kalman son de
grande interese nas aplicaci贸ns que usan ensaios baseados en modelos para avaliar os
seus par谩metros, entradas ou estados dos modelos virtuais dun certo sistema. Estes
procedementos p贸dense combinar co uso de xemelgos dixitais, hom贸logos virtuais
dun sistema f铆sico, co cal mante帽en un fluxo bidireccional de intercambio de informaci贸n. As medidas dispo帽铆beis procedentes dos sensores instalados nun sistema
f铆sico p贸dense combinar cos resultados obtidos da simulaci贸n do sistema virtual.
Deste xeito, este enfoque mellora o co帽ecemento das magnitudes que non poden ser
medidas directamente polos sensores. 脕 s煤a vez, os resultados da simulaci贸n dos
sistemas dos modelos virtuais poden servir para tomar decisi贸ns e aplicar medidas
correctivas ao sistema real.
En terceiro lugar, as t茅cnicas de co-simulaci贸n son necesarias cando un sistema
茅 dividido en varios subsistemas, coordinados a trav茅s do intercambio dun reducido
n煤mero de variables en momentos puntuais. Este 茅 o caso da maior parte das
aplicaci贸ns que seguen a estratexia de ensaios baseados en modelos, nos cales os
compo帽entes f铆sicos e virtuais se acoplan mediante unha comunicaci贸n en tempo
discreto. Como resultado as aplicaci贸ns ciberf铆sicas son esencialmente un exemplo
de co-simulaci贸n en tempo real, na que t贸dolos subsistemas necesitan cumprir os
requisitos de execuci贸n en tempo real. Debido 谩 presenza de compo帽entes f铆sicos, que
non poden reiterar os seus pasos de integraci贸n, o uso de esquemas expl铆citos 茅 polo
xeral necesario. Con todo, estes esquemas introducen erros asociados cos atrasos
derivados dunha interface de tempo discreto. Estes erros poden provocar resultados
incorrectos e incluso inestabilizar a co-simulaci贸n, de non seren eliminados. Esta
tese aborda a correcci贸n da co-simulaci贸n a trav茅s de m茅todos enerx茅ticos baseados
na potencia intercambiada polos subsistemas.
Este traballo concl煤e cun exemplo de aplicaci贸n ciberf铆sica, na que os compo帽entes
reais son conectados a un entorno virtual. Isto require o emprego de t贸dalas tecnolox铆as de ensaios baseadas en modelos presentadas ao longo desta tese
A cross-stack, network-centric architectural design for next-generation datacenters
This thesis proposes a full-stack, cross-layer datacenter architecture based on in-network computing and near-memory processing paradigms. The proposed datacenter architecture is built atop two principles: (1) utilizing commodity, off-the-shelf hardware (i.e., processor, DRAM, and network devices) with minimal changes to their architecture, and (2) providing a standard interface to the programmers for using the novel hardware. More specifically, the proposed datacenter architecture enables a smart network adapter to collectively compress/decompress data exchange between distributed DNN training nodes and assist the operating system in performing aggressive processor power management. It also deploys specialized memory modules in the servers, capable of performing general-purpose computation and network connectivity.
This thesis unlocks the potentials of hardware and operating system co-design in architecting application-transparent, near-data processing hardware for improving datacenter's performance, energy efficiency, and scalability. We evaluate the proposed datacenter architecture using a combination of full-system simulation, FPGA prototyping, and real-system experiments