Transforming Robotic Plans with Timed Automata to Solve Temporal Platform Constraints

Task planning for mobile robots typically uses an abstract planning domain that ignores the low-level details of the specific robot platform. Therefore, executing a plan on an actual robot often requires additional steps to deal with the specifics of the robot platform. Such a platform can be modeled with timed automata and a set of temporal constraints that need to be satisfied during execution. In this paper, we describe how to transform an abstract plan into a platform-specific action sequence that satisfies all platform constraints. The transformation procedure first transforms the plan into a timed automaton, which is then combined with the platform automata while removing all transitions that violate any constraint. We then apply reachability analysis on the resulting automaton. From any solution trace one can obtain the abstract plan extended by additional platform actions such that all platform constraints are satisfied. We describe the transformation procedure in detail and provide an evaluation in two real-world robotics scenarios.

Download Full-text

MODELING AND ANALYSIS OF REAL-TIME SYSTEMS WITH MUTEX COMPONENTS

International Journal of Foundations of Computer Science ◽

10.1142/s0129054112400382 ◽

2012 ◽

Vol 23 (04) ◽

pp. 831-851 ◽

Cited By ~ 2

Author(s):

GUOQIANG LI ◽

XIAOJUAN CAI ◽

SHOJI YUEN

Keyword(s):

Real Time ◽

Timed Automata ◽

Expressive Power ◽

Behavioral Model ◽

Parallel Composition ◽

Real Time Systems ◽

Modeling And Analysis ◽

Compositional System ◽

Time Systems ◽

Timed Automaton

Timed automata are commonly recognized as a formal behavioral model for real-time systems. For compositional system design, parallel composition of timed automata as proposed by Larsen et al. [22] is useful. Although parallel composition provides a general method for system construction, in the low level behavior, components often behave sequentially by passing control via communication. This paper proposes a behavioral model, named controller automata, to combine timed automata by focusing on the control passing between components. In a controller automaton, to each state a timed automaton is assigned. A timed automaton at a state may be preempted by the control passing to another state by a global labeled transition. A controller automaton properly extends the expressive power because of the stack, but this can make the reachability problem undecidable. Given a strict partial order over states, we show that this problem can be avoided and a controller automaton can be faithfully translated into a timed automaton.

Download Full-text

Tuning in scene-preferring cortex for mid-level visual features gives rise to selectivity across multiple levels of stimulus complexity

10.1101/2021.09.24.461733 ◽

2021 ◽

Author(s):

Shi Pui Donald Li ◽

Michael F. Bonner

Keyword(s):

Real World ◽

Computational Models ◽

Visual Stream ◽

Computational Theory ◽

Low Level ◽

Multiple Levels ◽

High Level ◽

Hierarchical Encoding ◽

Natural Statistics ◽

High Throughput Experiments

The scene-preferring portion of the human ventral visual stream, known as the parahippocampal place area (PPA), responds to scenes and landmark objects, which tend to be large in real-world size, fixed in location, and inanimate. However, the PPA also exhibits preferences for low-level contour statistics, including rectilinearity and cardinal orientations, that are not directly predicted by theories of scene- and landmark-selectivity. It is unknown whether these divergent findings of both low- and high-level selectivity in the PPA can be explained by a unified computational theory. To address this issue, we fit hierarchical computational models of mid-level tuning to the image-evoked fMRI responses of the PPA, and we performed a series of high-throughput experiments on these models. Our findings show that hierarchical encoding models of the PPA exhibit emergent selectivity across multiple levels of complexity, giving rise to high-level preferences along dimensions of real-world size, fixedness, and naturalness/animacy as well as low-level preferences for rectilinear shapes and cardinal orientations. These results reconcile disparate theories of PPA function in a unified model of mid-level visual representation, and they demonstrate how multifaceted selectivity profiles naturally emerge from the hierarchical computations of visual cortex and the natural statistics of images.

Download Full-text

Model Checking via Reachability Testing for Timed Automata

BRICS Report Series ◽

10.7146/brics.v4i29.18955 ◽

1997 ◽

Vol 4 (29) ◽

Cited By ~ 3

Author(s):

Luca Aceto ◽

Augusto Burgueno ◽

Kim G. Larsen

Keyword(s):

Model Checking ◽

Timed Automata ◽

Reachability Problem ◽

Liveness Properties ◽

Time Logic ◽

Definition Of ◽

Reachability Testing ◽

Time Systems ◽

Timed Automaton ◽

Theoretical Side

In this paper we develop an approach to model-checking for timed automata via reachability testing. As our specification formalism, we consider a dense-time logic with clocks. This logic may be used to express safety and bounded liveness properties of real-time systems. We show how to automatically synthesize, for every logical formula phi, a so-called test automaton T_phi in such a way that checking whether a system S satisfies the property phi can be reduced to a reachability question over the system obtained by making T_phi interact with S. <br />The testable logic we consider is both of practical and theoretical interest. On the practical side, we have used the logic, and the associated approach to model-checking via reachability testing it supports, in the specification and verification in Uppaal of a collision avoidance protocol. On the theoretical side, we show that the logic is powerful enough to permit the definition of characteristic properties, with respect to a timed version of<br />the ready simulation preorder, for nodes of deterministic, tau-free timed automata. This allows one to compute behavioural relations via our model-checking technique, therefore effectively reducing the problem of checking the existence of a behavioural relation among states of a timed automaton to a reachability problem.

Download Full-text

Using Timed Automata for a Priori Warnings and Planning for Timed Declarative Process Models

International Journal of Cooperative Information Systems ◽

10.1142/s0218843014400036 ◽

2014 ◽

Vol 23 (01) ◽

pp. 1440003 ◽

Cited By ~ 9

Author(s):

Fabrizio Maria Maggi ◽

Michael Westergaard

Keyword(s):

Timed Automata ◽

A Priori ◽

Resource Planning ◽

Process Models ◽

Modeling Languages ◽

Temporal Constraints ◽

A Posteriori ◽

Human Knowledge ◽

Extended Version ◽

Cpn Tools

Many processes are characterized by high variability, making traditional process modeling languages cumbersome or even impossible to be used for their description. This is especially true in cooperative environments relying heavily on human knowledge. Declarative languages, like Declare, alleviate this issue by not describing what to do step-by-step but by defining a set of constraints between actions that must not be violated during the process execution. Furthermore, in modern cooperative business, time is of utmost importance. Therefore, declarative process models should be able to take this dimension into consideration. Timed Declare has already previously been introduced to monitor temporal constraints at runtime, but it has until now only been possible to provide an alert when a constraint has already been violated without the possibility of foreseeing and avoiding such violations. In this paper, we introduce an extended version of Timed Declare with a formal timed semantics for the entire language. The semantics degenerates to the untimed semantics in the expected way. We also introduce a translation to timed automata, which allows us to detect inconsistencies in models prior to execution and to early detect that a certain task is time sensitive. This means that either the task cannot be executed after a deadline (or before a latency), or that constraints are violated unless it is executed before (or after) a certain time. This makes it possible to use declarative process models to provide a priori guidance instead of just a posteriori detecting that an execution is invalid. We also outline how a Declare model with time can be used in resource planning and how Declare has been integrated into CPN Tools.

Download Full-text

A Data Age Dependent Broadcast Forwarding Algorithm for Reliable Platooning Applications

Mobile Information Systems ◽

10.1155/2016/7489873 ◽

2016 ◽

Vol 2016 ◽

pp. 1-9

Author(s):

Marcus Larsson ◽

Magnus Jonsson ◽

Fredrik Warg ◽

Kristian Karlsson

Keyword(s):

Real World ◽

Measurement Data ◽

Original Data ◽

Data Packet ◽

Heavy Duty ◽

Low Level ◽

V2v Communication ◽

Age Dependent ◽

Broadcast Message ◽

Link Information

We propose a broadcast message forwarding algorithm for V2V communication in a platooning scenario for heavy duty trucks. The algorithm utilizes link information, which is piggybacked on the original data packet, to estimate which nodes are best suited to forward the packet. The aim is to reach all nodes in the platoon with as few forward messages as possible in order to avoid channel congestion. The algorithm is evaluated by simulation using real world V2V measurement data as input. We show that the algorithm performs almost as good as two ETSI standardized forwarding algorithms with respect to keeping the data age for the entire platoon at a low level. But when it comes to keeping the message intensity low, our algorithm outperforms the better of the ETSI algorithms by 35%.

Download Full-text

Integrating Low Level Symmetries into Reachability Analysis

Tools and Algorithms for the Construction and Analysis of Systems - Lecture Notes in Computer Science ◽

10.1007/3-540-46419-0_22 ◽

2000 ◽

pp. 315-330 ◽

Cited By ~ 17

Author(s):

Karsten Schmidt

Keyword(s):

Reachability Analysis ◽

Low Level

Download Full-text

Reachability analysis for timed automata using max-plus algebra

The Journal of Logic and Algebraic Programming ◽

10.1016/j.jlap.2011.10.004 ◽

2012 ◽

Vol 81 (3) ◽

pp. 298-313 ◽

Cited By ~ 9

Author(s):

Qi Lu ◽

Michael Madsen ◽

Martin Milata ◽

Søren Ravn ◽

Uli Fahrenberg ◽

...

Keyword(s):

Timed Automata ◽

Reachability Analysis

Download Full-text

Reshaping human intention in Human-Robot Interactions by robot moves

Interaction Studies ◽

10.1075/is.18068.dur ◽

2019 ◽

Vol 20 (3) ◽

pp. 530-560

Author(s):

Akif Durdu ◽

Aydan M. Erkmen ◽

Alper Yilmaz

Keyword(s):

Mobile Robots ◽

Hidden Markov Models ◽

Mobile Agents ◽

Markov Models ◽

Hidden Markov ◽

Experimental Setup ◽

Low Level ◽

Human Intention

Abstract This paper outlines the methodology and experiments associated with the reshaping of human intentions based on robot movements within Human-Robot Interactions (HRIs). Although studies on estimating human intentions are well studied in the literature, reshaping intentions through robot-initiated interactions is a new significant branching in the field of HRI. In this paper, we analyze how estimated human intentions can intentionally change through cooperation with mobile robots in real Human-Robot environments. This paper proposes an intention-reshaping system that includes either the Observable Operator Models (OOMs) or Hidden Markov Models (HMMs) to estimate human intention and decide which moves a robot should perform to reshape previously estimated human intentions into desired ones. At the low level, the system needs to track the locations of all mobile agents using cameras. We test our system on videos taken in a real HRI environment that has been developed as our experimental setup. The results show that OOMs are faster than HMMs and both models give correct decisions for testing sequences.

Download Full-text