8,549 research outputs found
Metastability-Containing Circuits
In digital circuits, metastability can cause deteriorated signals that
neither are logical 0 or logical 1, breaking the abstraction of Boolean logic.
Unfortunately, any way of reading a signal from an unsynchronized clock domain
or performing an analog-to-digital conversion incurs the risk of a metastable
upset; no digital circuit can deterministically avoid, resolve, or detect
metastability (Marino, 1981). Synchronizers, the only traditional
countermeasure, exponentially decrease the odds of maintained metastability
over time. Trading synchronization delay for an increased probability to
resolve metastability to logical 0 or 1, they do not guarantee success.
We propose a fundamentally different approach: It is possible to contain
metastability by fine-grained logical masking so that it cannot infect the
entire circuit. This technique guarantees a limited degree of metastability
in---and uncertainty about---the output.
At the heart of our approach lies a time- and value-discrete model for
metastability in synchronous clocked digital circuits. Metastability is
propagated in a worst-case fashion, allowing to derive deterministic
guarantees, without and unlike synchronizers. The proposed model permits
positive results and passes the test of reproducing Marino's impossibility
results. We fully classify which functions can be computed by circuits with
standard registers. Regarding masking registers, we show that they become
computationally strictly more powerful with each clock cycle, resulting in a
non-trivial hierarchy of computable functions
Interpolation Methods for Binary and Multivalued Logical Quantum Gate Synthesis
A method for synthesizing quantum gates is presented based on interpolation
methods applied to operators in Hilbert space. Starting from the diagonal forms
of specific generating seed operators with non-degenerate eigenvalue spectrum
one obtains for arity-one a complete family of logical operators corresponding
to all the one-argument logical connectives. Scaling-up to n-arity gates is
obtained by using the Kronecker product and unitary transformations. The
quantum version of the Fourier transform of Boolean functions is presented and
a Reed-Muller decomposition for quantum logical gates is derived. The common
control gates can be easily obtained by considering the logical correspondence
between the control logic operator and the binary propositional logic operator.
A new polynomial and exponential formulation of the Toffoli gate is presented.
The method has parallels to quantum gate-T optimization methods using powers of
multilinear operator polynomials. The method is then applied naturally to
alphabets greater than two for multi-valued logical gates used for quantum
Fourier transform, min-max decision circuits and multivalued adders
SAT based Enforcement of Domotic Effects in Smart Environments
The emergence of economically viable and efficient sensor technology provided impetus to the development of smart devices (or appliances). Modern smart environments are equipped with a multitude of smart devices and sensors, aimed at delivering intelligent services to the users of smart environments. The presence of these diverse smart devices has raised a major problem of managing environments. A rising solution to the problem is the modeling of user goals and intentions, and then interacting with the environments using user defined goals. `Domotic Effects' is a user goal modeling framework, which provides Ambient Intelligence (AmI) designers and integrators with an abstract layer that enables the definition of generic goals in a smart environment, in a declarative way, which can be used to design and develop intelligent applications. The high-level nature of domotic effects also allows the residents to program their personal space as they see fit: they can define different achievement criteria for a particular generic goal, e.g., by defining a combination of devices having some particular states, by using domain-specific custom operators. This paper describes an approach for the automatic enforcement of domotic effects in case of the Boolean application domain, suitable for intelligent monitoring and control in domotic environments. Effect enforcement is the ability to determine device configurations that can achieve a set of generic goals (domotic effects). The paper also presents an architecture to implement the enforcement of Boolean domotic effects, and results obtained from carried out experiments prove the feasibility of the proposed approach and highlight the responsiveness of the implemented effect enforcement architectur
- âŠ