613 research outputs found
Emerging research directions in computer science : contributions from the young informatics faculty in Karlsruhe
In order to build better human-friendly human-computer interfaces,
such interfaces need to be enabled with capabilities to perceive
the user, his location, identity, activities and in particular his interaction
with others and the machine. Only with these perception capabilities
can smart systems ( for example human-friendly robots or smart environments) become posssible. In my research I\u27m thus focusing on the
development of novel techniques for the visual perception of humans and
their activities, in order to facilitate perceptive multimodal interfaces,
humanoid robots and smart environments. My work includes research
on person tracking, person identication, recognition of pointing gestures,
estimation of head orientation and focus of attention, as well as
audio-visual scene and activity analysis. Application areas are humanfriendly
humanoid robots, smart environments, content-based image and
video analysis, as well as safety- and security-related applications. This
article gives a brief overview of my ongoing research activities in these
areas
Prospective communications research to support fly by light/power by wire
A NASA Research Grant NAG-1-1309, Distributed Fiber Optic Systems for Commercial Aircraft, was awarded during July 1991. This report primarily constitutes a summary of findings of the original background research done at that time. NASA is embarking on a research project to design the next generation of commercial aircraft, fly by light/power by wire. The objectives of this effort are to improve commercial aircraft design by (1) reducing the weight of the aircraft to improve efficiency and (2) improving the fault tolerance and safety of the aircraft by enhancing current systems with new technologies or introducing new systems into the aircraft
Future benefits and applications of intelligent on-board processing to VSAT services
The trends and roles of VSAT services in the year 2010 time frame are examined based on an overall network and service model for that period. An estimate of the VSAT traffic is then made and the service and general network requirements are identified. In order to accommodate these traffic needs, four satellite VSAT architectures based on the use of fixed or scanning multibeam antennas in conjunction with IF switching or onboard regeneration and baseband processing are suggested. The performance of each of these architectures is assessed and the key enabling technologies are identified
Applying Formal Methods to Networking: Theory, Techniques and Applications
Despite its great importance, modern network infrastructure is remarkable for
the lack of rigor in its engineering. The Internet which began as a research
experiment was never designed to handle the users and applications it hosts
today. The lack of formalization of the Internet architecture meant limited
abstractions and modularity, especially for the control and management planes,
thus requiring for every new need a new protocol built from scratch. This led
to an unwieldy ossified Internet architecture resistant to any attempts at
formal verification, and an Internet culture where expediency and pragmatism
are favored over formal correctness. Fortunately, recent work in the space of
clean slate Internet design---especially, the software defined networking (SDN)
paradigm---offers the Internet community another chance to develop the right
kind of architecture and abstractions. This has also led to a great resurgence
in interest of applying formal methods to specification, verification, and
synthesis of networking protocols and applications. In this paper, we present a
self-contained tutorial of the formidable amount of work that has been done in
formal methods, and present a survey of its applications to networking.Comment: 30 pages, submitted to IEEE Communications Surveys and Tutorial
TorchProbe: Fuzzing Dynamic Deep Learning Compilers
Static and dynamic computational graphs represent two distinct approaches to
constructing deep learning frameworks. The former prioritizes compiler-based
optimizations, while the latter focuses on programmability and
user-friendliness. The recent release of PyTorch 2.0, which supports compiling
arbitrary deep learning programs in Python, signifies a new direction in the
evolution of deep learning infrastructure to incorporate compiler techniques in
a more dynamic manner and support more dynamic language features like dynamic
control flows and closures. Given PyTorch's seamless integration with Python,
its compiler aims to support arbitrary deep learning code written in Python.
However, the inherent dynamism of Python poses challenges to the completeness
and robustness of the compiler. While recent research has introduced fuzzing to
test deep learning compilers, there is still a lack of comprehensive analysis
on how to test dynamic features. To address this issue, we propose several code
transformations to generate test cases involving dynamic features. These
transformations preserve the program's semantics, ensuring that any discrepancy
between the transformed and original programs indicates the presence of a bug.
Through our approach, we have successfully identified twenty previously unknown
bugs in the PyTorch compiler and its underlying tensor compiler Triton
Architecting Data Centers for High Efficiency and Low Latency
Modern data centers, housing remarkably powerful computational capacity, are built in massive scales and consume a huge amount of energy. The energy consumption of data centers has mushroomed from virtually nothing to about three percent of the global electricity supply in the last decade, and will continuously grow. Unfortunately, a significant fraction of this energy consumption is wasted due to the inefficiency of current data center architectures, and one of the key reasons behind this inefficiency is the stringent response latency requirements of the user-facing services hosted in these data centers such as web search and social networks. To deliver such low response latency, data center operators often have to overprovision resources to handle high peaks in user load and unexpected load spikes, resulting in low efficiency.
This dissertation investigates data center architecture designs that reconcile high system efficiency and low response latency. To increase the efficiency, we propose techniques that understand both microarchitectural-level resource sharing and system-level resource usage dynamics to enable highly efficient co-locations of latency-critical services and low-priority batch workloads. We investigate the resource sharing on real-system simultaneous multithreading (SMT) processors to enable SMT co-locations by precisely predicting the performance interference. We then leverage historical resource usage patterns to further optimize the task scheduling algorithm and data placement policy to improve the efficiency of workload co-locations. Moreover, we introduce methodologies to better manage the response latency by automatically attributing the source of tail latency to low-level architectural and system configurations in both offline load testing environment and online production environment. We design and develop a response latency evaluation framework at microsecond-level precision for data center applications, with which we construct statistical inference procedures to attribute the source of tail latency. Finally, we present an approach that proactively enacts carefully designed causal inference micro-experiments to diagnose the root causes of response latency anomalies, and automatically correct them to reduce the response latency.PHDComputer Science & EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/144144/1/yunqi_1.pd
Proceedings of the 21st Conference on Formal Methods in Computer-Aided Design – FMCAD 2021
The Conference on Formal Methods in Computer-Aided Design (FMCAD) is an annual conference on the theory and applications of formal methods in hardware and system verification. FMCAD provides a leading forum to researchers in academia and industry for presenting and discussing groundbreaking methods, technologies, theoretical results, and tools for reasoning formally about computing systems. FMCAD covers formal aspects of computer-aided system design including verification, specification, synthesis, and testing
An approach to enacting business process models in support of the life cycle of integrated manufacturing systems
The complexity of enterprise engineering processes requires the application of
reference architectures as means of guiding the achievement of an adequate level of
business integration. This research aims to address important aspects of this
requirement by associating the formalism of reference architectures to various life cycle
phases of integrating manufacturing systems (IMS) and enabling their use in addressing
contemporary system engineering issues.
In pursuit of this aim, the following research activities were carried out: (1) to
devise a framework which supports key phases of the IMS life cycle and (2) to populate
part of this framework with an initial combination of architectures which can be
encapsulated into a computer-aided systems engineering environment. This has led to
the creation of a workbench capable of providing support for modelling, analysis,
simulation, rapid-prototyping, configuration and run-time operation of an IMS, based
on a consistent set of models associated with the engineering processes involved. The
research effort concentrated on selecting and investigating the use of appropriate
formalisms which underpin a selection of architectures and tools (i. e. CIM-OSA, Petrinets,
object-oriented methods and CIM-BIOSYS), this by designing, implementing,
applying and testing the workbench.
The main contribution of this research is to demonstrate that it is possible to
retain an adequate level of formalism, via computational structures and models, which
extend through the IMS life cycle from a conceptual description of the system through
to actions that the system performs when operating. The underlying methodology
which supported this contribution is based on enacting models of system behaviour
which encode important coordination aspects of manufacturing systems. The strategy
for demonstrating the incorporation of formalism to the IMS life cycle was to enable
the aggregation into a workbench of knowledge of 'what' the system is expected to
achieve (i. e. 'problems' to be addressed) and 'how' the system can achieve it (i. e
possible 'solutions'). Within the workbench, such a knowledge is represented through
an amalgamation of business process modelling and object-oriented modelling
approaches which, when adequately manipulated, can lead to business integration
- …