The Bottom-Up Position Tree Automaton and the Father Automaton

2020 ◽  
pp. 1-18
Author(s):  
Samira Attou ◽  
Ludovic Mignot ◽  
Djelloul Ziadi
Keyword(s):  
Tree Automaton ◽  
Tree Automata ◽  
Top Down ◽  
Bottom Up ◽  
Regular Tree ◽  
The One ◽  
Tree Expression

The conversion of a given regular tree expression into a tree automaton has been widely studied. However, classical interpretations are based upon a top-down interpretation of tree automata. In this paper, we propose new constructions based on Gluskov’s one and on the one by Ilie and Yu using a bottom-up interpretation. One of the main goals of this technique is to consider as a next step the links with deterministic recognizers, something which cannot be done with classical top-down approaches.

Operational State Complexity of Subtree-Free Regular Tree Languages

2016 ◽  
Vol 27 (06) ◽  
pp. 705-724
Author(s):  
Sang-Ki Ko ◽  
Hae-Sung Eom ◽  
Yo-Sub Han
Keyword(s):  
The State ◽  
Tree Automaton ◽  
Top Down ◽  
Tree Language ◽  
Worst Case ◽  
Bottom Up ◽  
State Complexity ◽  
Regular Tree ◽  
Tree Languages

We introduce subtree-free regular tree languages that are closely related to XML schemas and investigate the state complexity of basic operations on subtree-free regular tree languages. The state complexity of an operation for regular tree languages is the number of states that are sufficient and necessary in the worst-case for the minimal deterministic ranked tree automaton that accepts the tree language obtained from the operation. We establish the precise state complexity of (sequential, parallel) concatenation, (bottom-up, top-down) star, intersection and union for subtree-free regular tree languages.

HYPER-MINIMIZATION FOR DETERMINISTIC TREE AUTOMATA

2013 ◽  
Vol 24 (06) ◽  
pp. 815-830 ◽  
Author(s):  
ARTUR JEŻ ◽  
ANDREAS MALETTI
Keyword(s):  
Finite Difference ◽  
Minimization Problem ◽  
Fast Algorithms ◽  
Input Tree ◽  
Tree Automaton ◽  
Tree Automata ◽  
Compression Technique ◽  
Bottom Up ◽  
Finite State ◽  
Transition Table

Hyper-minimization is a recent automaton compression technique that can reduce the size of an automaton beyond the limits imposed by classical minimization. The additional compression power is enabled by allowing a finite difference in the represented language. The necessary theory for hyper-minimization is developed for (bottom-up) deterministic tree automata. The hyper-minimization problem for deterministic tree automata is reduced to the hyper-minimization problem for deterministic finite-state string automata, for which fast algorithms exist. The fastest algorithm obtained in this way runs in time [Formula: see text], where m is the size of the transition table and n is the number of states of the input tree automaton.

scholarly journals A Congruence-Based Perspective on Finite Tree Automata

2022 ◽  
Vol 184 (1) ◽  
pp. 1-47
Author(s):  
Pierre Ganty ◽  
Elena Gutiérrez ◽  
Pedro Valero
Keyword(s):  
Expressive Power ◽  
Tree Automata ◽  
Minimization Algorithm ◽  
Top Down ◽  
Finite Tree ◽  
Bottom Up ◽  
Original Result

We provide new insights on the determinization and minimization of tree automata using congruences on trees. From this perspective, we study a Brzozowski’s style minimization algorithm for tree automata. First, we prove correct this method relying on the following fact: when the automata-based and the language-based congruences coincide, determinizing the automaton yields the minimal one. Such automata-based congruences, in the case of word automata, are defined using pre and post operators. Now we extend these operators to tree automata, a task that is particularly challenging due to the reduced expressive power of deterministic top-down (or equivalently co-deterministic bottom-up) automata. We leverage further our framework to offer an extension of the original result by Brzozowski for word automata.

scholarly journals Bottom-Up derivatives of tree expressions

2021 ◽  
Vol 55 ◽  
pp. 4
Author(s):  
Samira Attou ◽  
Ludovic Mignot ◽  
Djelloul Ziadi
Keyword(s):  
Fixed Point ◽  
Tree Automaton ◽  
Bottom Up ◽  
Regular Tree ◽  
Partial Derivatives ◽  
New Family ◽  
Derivatives Of

In this paper, we extend the notion of (word) derivatives and partial derivatives due to (respectively) Brzozowski and Antimirov to tree derivatives using already known inductive formulae of quotients. We define a new family of extended regular tree expressions (using negation or intersection operators), and we show how to compute a Brzozowski-like inductive tree automaton; the fixed point of this construction, when it exists, is the derivative tree automaton. Such a deterministic tree automaton can be used to solve the membership test efficiently: the whole structure is not necessarily computed, and the derivative computations can be performed in parallel. We also show how to solve the membership test using our (Bottom-Up) partial derivatives, without computing an automaton.

Are You Being Served?

2013 ◽  
pp. 294-312
Author(s):  
Jeremy Millard
Keyword(s):  
Public Services ◽  
Smart Phones ◽  
Data Driven ◽  
Top Down ◽  
Local Data ◽  
Bottom Up ◽  
Current Trends ◽  
Huge Data ◽  
Service Environments ◽  
The One

In terms of public services, governments do not yet know how to treat users as different and unique individuals. At worst, users are still considered an undifferentiated mass, or at best as segments. However, the benefits of universal personalisation in public services are within reach technologically through e-government developments. Universal personalisation will involve achieving a balance between top-down government- and data-driven services, on the one hand, and bottom-up self-directed and user-driven services on the other. There are at least three main technological, organisational and societal drivers. First, top-down data-driven, often automatic, services based on the huge data resources available in the cloud and the technologies enabling the systematic exploitation of these by governments. Second, increasing opportunities for users themselves or their intermediaries to select or create their own service environments, bottom-up, through ‘user-driven’ services, drawing directly on the data cloud. Third, a move to ‘everyday’, location-driven e-government based largely on mobile smart phones using GPS and local data clouds, where public services are offered depending on where people are as well as who they are and what they are doing. This paper examines practitioners and researchers and describes model current trends based on secondary research and literature review.

A space for identity: the case of Lebanon’s naturalised Palestinians

2018 ◽  
Author(s):  
Hind Ghandour
Keyword(s):  
Human Rights ◽  
The Other ◽  
Top Down ◽  
National Belonging ◽  
Bottom Up ◽  
Paradigmatic Shift ◽  
Naturalized Citizens ◽  
National Discourses ◽  
The One

This chapter examines a segment of Palestinians who were granted citizenship in Lebanon through a process of tawtin, a naturalization strategy underpinned by notions of national belonging and identity. It draws upon interviews and observations with naturalized citizens and refugees to illustrate and reveal patterns of citizenship practice that challenge national discourses of tawtin, and suggest the emergence of a paradigm that posits citizenship-as-rights, and not identity.  Despite the dichotomous discourse that posits Palestinian identity in dialectic to citizenship, naturalized Palestinians constructed dynamic spaces for both to exist, somewhat harmoniously. Despite the globalization of human rights and the rise of universal personhood, access to rights remains inextricably bound and dependent upon access to citizenship. Analyses of citizenship practice remains, for the most part, conscripted to frameworks that posit citizenship-as identity on the one hand, and the subsequent emergence of citizenship-as-rights on the other. Belying these existing frameworks is a negotiation and re-negotiation of citizenship by individuals that inherently challenges them from within. This necessitates a paradigmatic shift from the top-down lens within which tawtin of Palestinians in Lebanon is presented, towards a bottom-up approach that explores the individuals’ agency in its conceptualization. 

scholarly journals The Curious Incident of Attention in Multisensory Integration: Bottom-up vs. Top-down

2016 ◽  
Vol 29 (6-7) ◽  
pp. 557-583 ◽  
Author(s):  
Emiliano Macaluso ◽  
Uta Noppeney ◽  
Durk Talsma ◽  
Tiziana Vercillo ◽  
Jess Hartcher-O’Brien ◽  
...  
Keyword(s):  
Prior Knowledge ◽  
Multisensory Integration ◽  
The Other ◽  
Top Down ◽  
Bottom Up ◽  
Stimulus Properties ◽  
Low Level ◽  
Other Hand ◽  
Current Task ◽  
The One

The role attention plays in our experience of a coherent, multisensory world is still controversial. On the one hand, a subset of inputs may be selected for detailed processing and multisensory integration in a top-down manner, i.e., guidance of multisensory integration by attention. On the other hand, stimuli may be integrated in a bottom-up fashion according to low-level properties such as spatial coincidence, thereby capturing attention. Moreover, attention itself is multifaceted and can be describedviaboth top-down and bottom-up mechanisms. Thus, the interaction between attention and multisensory integration is complex and situation-dependent. The authors of this opinion paper are researchers who have contributed to this discussion from behavioural, computational and neurophysiological perspectives. We posed a series of questions, the goal of which was to illustrate the interplay between bottom-up and top-down processes in various multisensory scenarios in order to clarify the standpoint taken by each author and with the hope of reaching a consensus. Although divergence of viewpoint emerges in the current responses, there is also considerable overlap: In general, it can be concluded that the amount of influence that attention exerts on MSI depends on the current task as well as prior knowledge and expectations of the observer. Moreover stimulus properties such as the reliability and salience also determine how open the processing is to influences of attention.

A minimization algorithm for fuzzy top-down tree automata over lattices

2020 ◽  
pp. 1-10
Author(s):  
M. Ghorani ◽  
S. Garhwal
Keyword(s):  
Minimization Problem ◽  
Time Complexity ◽  
Tree Automaton ◽  
Tree Automata ◽  
Minimization Algorithm ◽  
Top Down ◽  
Minimal Form ◽  
Minimization Algorithms ◽  
The Given

In this paper, we study fuzzy top-down tree automata over lattices ( LTA s , for short). The purpose of this contribution is to investigate the minimization problem for LTA s . We first define the concept of statewise equivalence between two LTA s . Thereafter, we show the existence of the statewise minimal form for an LTA . To this end, we find a statewise irreducible LTA which is equivalent to a given LTA . Then, we provide an algorithm to find the statewise minimal LTA and by a theorem, we show that the output statewise minimal LTA is statewise equivalent to the given input. Moreover, we compute the time complexity of the given algorithm. The proposed algorithm can be applied to any given LTA and, unlike some minimization algorithms given in the literature, the input doesn’t need to be a complete, deterministic, or reduced lattice-valued tree automaton. Finally, we provide some examples to show the efficiency of the presented algorithm.

An Efficient Algorithm for the Construction of the Equation Tree Automaton

2018 ◽  
Vol 29 (06) ◽  
pp. 951-978
Author(s):  
Ludovic Mignot ◽  
Nadia Ouali-Sebti ◽  
Djelloul Ziadi
Keyword(s):  
Regular Expression ◽  
Maximal Rank ◽  
Space Complexity ◽  
Full Description ◽  
Time And Space ◽  
Regular Tree ◽  
The One ◽  
Time And Space Complexity ◽  
Complexity Algorithm ◽  
Tree Expression

Champarnaud et al., and Khorsi et al. show how to compute the equation automaton of a word regular expression [Formula: see text] via the C-continuations. Kuske and Meinecke extend the computation of the equation automaton to a regular tree expression [Formula: see text] over a ranked alphabet [Formula: see text] and produce a [Formula: see text] time and space complexity algorithm, where [Formula: see text] is the maximal rank of a symbol occurring in [Formula: see text] and [Formula: see text] is the size of the syntax tree of [Formula: see text]. In this paper, we give a full description of an algorithm based on the acyclic minimization of Revuz in order to compute the pseudo-continuations from the C-continuations. Our algorithm, which is performed in [Formula: see text] time and space complexity, where [Formula: see text] is the number of states of the produced automaton, is more efficient than the one obtained by Kuske and Meinecke since [Formula: see text]. Moreover, our algorithm is an output-sensitive algorithm, i.e. the complexity of which is based on the size of the produced automaton.

Bridging the gap: Dynamics as a unified view of cognition

2001 ◽  
Vol 24 (1) ◽  
pp. 45-46 ◽  
Author(s):  
Derek Harter ◽  
Arthur C. Graesser ◽  
Stan Franklin
Keyword(s):  
Cognitive Processes ◽  
Cognitive Abilities ◽  
Gap Dynamics ◽  
Dynamical Models ◽  
Top Down ◽  
Bottom Up ◽  
Computational Approaches ◽  
Unified View ◽  
The One ◽  
Biological Organisms

Top-down dynamical models of cognitive processes, such as the one presented by Thelen et al., are important pieces in understanding the development of cognitive abilities in humans and biological organisms. Unlike standard symbolic computational approaches to cognition, such dynamical models offer the hope that they can be connected with more bottom-up, neurologically inspired dynamical models to provide a complete view of cognition at all levels. We raise some questions about the details of their simulation and about potential limitations of top-down dynamical models.

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