8 research outputs found
Design Space Re-Engineering for Power Minimization in Modern Embedded Systems
Power minimization is a critical challenge for modern embedded system design. Recently, due to the rapid increase of system's complexity and
the power density, there is a growing need for power control techniques at various design levels. Meanwhile, due to technology scaling, leakage power has become a significant part of power dissipation in the CMOS circuits and new techniques are needed to reduce leakage power.
As a result, many new power minimization techniques have been proposed such as voltage island, gate sizing, multiple supply and threshold voltage, power gating and input vector control, etc. These design options further
enlarge the design space and make it prohibitively expensive to explore
for the most energy efficient design solution.
Consequently, heuristic algorithms and randomized
algorithms are frequently used to explore the design space, seeking sub-optimal
solutions to meet the time-to-market requirements. These algorithms are
based on the idea of truncating the design space
and restricting the search in a subset of the original design space. While this approach can effectively reduce the runtime of searching, it may also exclude high-quality design solutions and cause design quality degradation.
When the solution to one problem is used as the base for another problem, such solution quality degradation will accumulate. In modern electronics system design, when several such algorithms are used in series to solve problems in different design levels, the final solution can be far off the optimal one.
In my Ph.D. work, I develop a {\em re-engineering} methodology to
facilitate exploring the design space of power efficient embedded systems design.
The direct goal is to enhance the performance of existing low power
techniques. The methodology is based on the idea that design quality can be improved
via iterative ``re-shaping'' the design space based on the ``bad'' structure
in the obtained design solutions; the searching run-time can be reduced
by the guidance from previous exploration. This approach can be
described in three phases: (1) apply the existing techniques to obtain
a sub-optimal solution; (2) analyze the solution and expand the design
space accordingly; and (3) re-apply the technique to re-explore the
enlarged design space.
We apply this methodology at different levels of embedded system design to
minimize power: (i) switching power reduction in sequential logic synthesis;
(ii) gate-level static leakage current reduction; (iii) dual threshold voltage CMOS
circuits design; and (iv) system-level energy-efficient detection scheme for
wireless sensor networks. An extensive amount of experiments have been conducted
and the results have shown that this methodology can effectively enhance
the power efficiency of the existing embedded system design flows with very little
overhead
Order and structure in syntax I
This book reconsiders the role of order and structure in syntax, focusing on fundamental issues such as word order and grammatical functions. The first group of papers in the collection asks what word order can tell us about syntactic structure, using evidence from V2, object shift, word order gaps and different kinds of movement. The second group of papers all address the issue of subjecthood in some way, and examine how certain subject properties vary across languages: expression of subjects, expletive subjects, quirky and locative subjects. All of the papers address in some way the tension between modelling what can vary across languages whilst improving our understanding of what might be universal to human language
Word order and syntactic structure
This book reconsiders the role of order and structure in syntax, focusing on fundamental issues such as word order and grammatical functions. The first group of papers in the collection asks what word order can tell us about syntactic structure, using evidence from V2, object shift, word order gaps and different kinds of movement. The second group of papers all address the issue of subjecthood in some way, and examine how certain subject properties vary across languages: expression of subjects, expletive subjects, quirky and locative subjects. All of the papers address in some way the tension between modelling what can vary across languages whilst improving our understanding of what might be universal to human language
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Aspects of emergent cyclicity in language and computation
This thesis has four parts, which correspond to the presentation and development of a theoretical
framework for the study of cognitive capacities qua physical phenomena, and a case study of locality conditions over natural languages.
Part I deals with computational considerations, setting the tone of the rest of the thesis, and introducing and defining critical concepts like ‘grammar’, ‘automaton’, and the relations between them
. Fundamental questions concerning the place of formal language theory in
linguistic inquiry, as well as the expressibility of linguistic and computational concepts in
common terms, are raised in this part.
Part II further explores the issues addressed in Part I with particular emphasis on how
grammars are implemented by means of automata, and the properties of the formal languages
that these automata generate. We will argue against the equation between effective computation
and function-based computation, and introduce examples of computable procedures which are
nevertheless impossible to capture using traditional function-based theories. The connection
with cognition will be made in the light of dynamical frustrations: the irreconciliable tension
between mutually incompatible tendencies that hold for a given dynamical system. We will
provide arguments in favour of analyzing natural language as emerging from a tension between
different systems (essentially, semantics and morpho-phonology) which impose orthogonal
requirements over admissible outputs. The concept of level of organization or scale comes to
the foreground here; and apparent contradictions and incommensurabilities between concepts
and theories are revisited in a new light: that of dynamical nonlinear systems which are
fundamentally frustrated. We will also characterize the computational system that emerges from
such an architecture: the goal is to get a syntactic component which assigns the simplest
possible structural description to sub-strings, in terms of its computational complexity. A
system which can oscillate back and forth in the hierarchy of formal languages in assigning
structural representations to local domains will be referred to as a computationally mixed
system.
Part III is where the really fun stuff starts. Field theory is introduced, and its applicability to
neurocognitive phenomena is made explicit, with all due scale considerations. Physical and
mathematical concepts are permanently interacting as we analyze phrase structure in terms of
pseudo-fractals (in Mandelbrot’s sense) and define syntax as a (possibly unary) set of
topological operations over completely Hausdorff (CH) ultrametric spaces. These operations, which makes field perturbations interfere, transform that initial completely Hausdorff
ultrametric space into a metric, Hausdorff space with a weaker separation axiom. Syntax, in this
proposal, is not ‘generative’ in any traditional sense –except the ‘fully explicit theory’ one-:
rather, it partitions (technically, ‘parametrizes’) a topological space. Syntactic dependencies are
defined as interferences between perturbations over a field, which reduce the total entropy of
the system per cycles, at the cost of introducing further dimensions where attractors
corresponding to interpretations for a phrase marker can be found.
Part IV is a sample of what we can gain by further pursuing the physics of language approach,
both in terms of empirical adequacy and theoretical elegance, not to mention the unlimited
possibilities of interdisciplinary collaboration. In this section we set our focus on island
phenomena as defined by Ross (1967), critically revisiting the most relevant literature on this
topic, and establishing a typology of constructions that are strong islands, which cannot be
violated. These constructions are particularly interesting because they limit the phase space of
what is expressible via natural language, and thus reveal crucial aspects of its underlying
dynamics. We will argue that a dynamically frustrated system which is characterized by
displaying mixed computational dependencies can provide straightforward characterizations of
cyclicity in terms of changes in dependencies in local domains
Social work with airports passengers
Social work at the airport is in to offer to passengers social services. The main
methodological position is that people are under stress, which characterized by a
particular set of characteristics in appearance and behavior. In such circumstances
passenger attracts in his actions some attention. Only person whom he trusts can help him
with the documents or psychologically
Safety and Reliability - Safe Societies in a Changing World
The contributions cover a wide range of methodologies and application areas for safety and reliability that contribute to safe societies in a changing world. These methodologies and applications include: - foundations of risk and reliability assessment and management
- mathematical methods in reliability and safety
- risk assessment
- risk management
- system reliability
- uncertainty analysis
- digitalization and big data
- prognostics and system health management
- occupational safety
- accident and incident modeling
- maintenance modeling and applications
- simulation for safety and reliability analysis
- dynamic risk and barrier management
- organizational factors and safety culture
- human factors and human reliability
- resilience engineering
- structural reliability
- natural hazards
- security
- economic analysis in risk managemen
The Austronesian languages
This is a revised edition of the 2009 The Austronesian languages, which was published as a paperback in the then Pacific Linguistics series (ISBN 9780858836020). This revision includes typographical corrections, an improved index, and various minor content changes. The release of the open access edition serves to meet the strong ongoing demand for this important handbook, of which only 200 copies of the first edition were printed. This is the first single-authored book that attempts to describe the Austronesian language family in its entirety. Topics covered include: the physical and cultural background, official and national languages, largest and smallest languages in all major geographical regions, language contact, sound systems, linguistic palaeontology, morphology, syntax, the history of scholarship on Austronesian languages, and a critical assessment of the reconstruction of Proto Austronesian phonology.Australian National University, College of Asia and the Pacifi