5 research outputs found
Cellular Automata as a Model of Physical Systems
Cellular Automata (CA), as they are presented in the literature, are abstract
mathematical models of computation. In this pa- per we present an alternate
approach: using the CA as a model or theory of physical systems and devices.
While this approach abstracts away all details of the underlying physical
system, it remains faithful to the fact that there is an underlying physical
reality which it describes. This imposes certain restrictions on the types of
computations a CA can physically carry out, and the resources it needs to do
so. In this paper we explore these and other consequences of our
reformalization.Comment: To appear in the Proceedings of AUTOMATA 200
Is there a physically universal cellular automaton or Hamiltonian?
It is known that both quantum and classical cellular automata (CA) exist that
are computationally universal in the sense that they can simulate, after
appropriate initialization, any quantum or classical computation, respectively.
Here we introduce a different notion of universality: a CA is called physically
universal if every transformation on any finite region can be (approximately)
implemented by the autonomous time evolution of the system after the complement
of the region has been initialized in an appropriate way. We pose the question
of whether physically universal CAs exist. Such CAs would provide a model of
the world where the boundary between a physical system and its controller can
be consistently shifted, in analogy to the Heisenberg cut for the quantum
measurement problem. We propose to study the thermodynamic cost of computation
and control within such a model because implementing a cyclic process on a
microsystem may require a non-cyclic process for its controller, whereas
implementing a cyclic process on system and controller may require the
implementation of a non-cyclic process on a "meta"-controller, and so on.
Physically universal CAs avoid this infinite hierarchy of controllers and the
cost of implementing cycles on a subsystem can be described by mixing
properties of the CA dynamics. We define a physical prior on the CA
configurations by applying the dynamics to an initial state where half of the
CA is in the maximum entropy state and half of it is in the all-zero state
(thus reflecting the fact that life requires non-equilibrium states like the
boundary between a hold and a cold reservoir). As opposed to Solomonoff's
prior, our prior does not only account for the Kolmogorov complexity but also
for the cost of isolating the system during the state preparation if the
preparation process is not robust.Comment: 27 pages, 1 figur
Aplicaci贸n de vida artificial al estudio de vacunas para el control del virus de papiloma humano tipo 16
Este trabajo de investigaci贸n presenta un modelo de vida artificial inspirado en el ciclo de vida del virus de papiloma humano tipo 16 (como agente etiol贸gico de c谩ncer cervical), en su interacci贸n con el sistema inmune humano y frente al desaf铆o que representa una vacuna terap茅utica. Concebido como un sistema complejo y caracterizado mediante t茅cnicas de vida artificial, se dise帽a un modelo conceptual y se construye un prototipo funcional que permite simular esta interacci贸n, considerando el conocimiento biol贸gico que actualmente se tiene de estos procesos. La caracterizaci贸n biol贸gica y mecanismos que surgen a partir de la interacci贸n entre pat贸geno y hu茅sped, y el desarrollo de un proceso infeccioso cuya persistencia puede conducir al desarrollo de c谩ncer cervical, permite definir un modelo conceptual en t茅rminos de reglas, puntos de chequeo, estados, transiciones e interacciones. Aunado a la caracterizaci贸n del ciclo de vida HPV16, cuyo modelo y prototipo fue presentado previamente en (Escobar-Ospina, M.E. y G贸mez-Perdomo, J., 2013), el dise帽o del modelo conceptual y la construcci贸n del prototipo funcional de la aplicaci贸n de vida artificial que actualmente se presenta, consideran la caracterizaci贸n biol贸gica de varias poblaciones celulares involucradas, incluidos sus procesos de diferenciaci贸n, proliferaci贸n y muerte celular programada. As铆 mismo, se incluye la caracterizaci贸n de v铆as de se帽alizaci贸n de un grupo de receptores claves en la respuesta inmune (TLRs), y tambi茅n cinco (5) grupos de familias de citoquinas que incluyen cuarenta y ocho (48) diferentes miembros, perfilando sus componentes y modelando patrones de expresi贸n que se observan en respuestas pro-inflamatorias y anti-inflamatorias. A partir de estos componentes y sus interacciones, surge la din谩mica que permite simular la respuesta del sistema inmune humano ante la detecci贸n y evoluci贸n del proceso infeccioso causado por HPV16. A este conjunto, se suman las herramientas que permiten simular la aplicaci贸n de algunos tipos de vacunas terap茅uticas que modifican el comportamiento del sistema inmune. El reconocimiento de las poblaciones celulares, receptores y citoquinas, frente al proceso infeccioso desencadenado por HPV16, aunado al conocimiento biol贸gico que actualmente se tiene, hace posible simular estos microambientes en aras de observar procesos de regresi贸n o progresi贸n de la enfermedad, luego de la aplicaci贸n de una vacuna terap茅utica cuyo objetivo se encuentre dirigido hacia alguno de los componentes que intervienen en el modelo que se presenta (prote铆nas virales, cascadas de se帽alizaci贸n, expresi贸n de citoquinas). La construcci贸n de este modelo busca apoyar procesos de simulaci贸n en actividades de investigaci贸n para el desarrollo de vacunas que procuren controlar enfermedades causadas por infecci贸n HPV16.Doctorad
Cellular automata as a model of physical systems
Cellular Automata (CA), as they are presented in the literature, are abstract mathematical models of computation. In this pa- per we present an alternate approach: using the CA as a model or theory of physical systems and devices. While this approach abstracts away all details of the underlying physical system, it remains faithful to the fact that there is an underlying physical reality which it describes. This imposes certain restrictions on the types of computations a CA can physically carry out, and the resources it needs to do so. In this paper we explore these and other consequences of our reformalization