Department of Computer Sciences
Algorithmic Robotics, Computational Geometry
Mathamatics and Computer Science, Amirkabir University of Technology, Tehran, Iran
Algorithmic Robotics, Computational Geometry
Mathematics and Computer Science, Amirkabir University of Technology, Tehran, Iran
Computational Geometry
Mathematics and Computer Science, Amirkabir University of Technology, Tehran, Iran
I am teaching and researching as an assistant professor in the Computer Science Group of the Mathematical Sciences Department at Tarbiat Modares University. My field of interest includes Algorithmic Robotics and Computational Geometry.
This article examines the selection of a robot's actuation and sensing hardware to minimize the cost of that design while ensuring that the robot is capable of carrying out a plan to complete a task. Its primary contribution is in the study of the hardness of reasonable formal models for that minimization problem. Specifically, for the case in which sensing hardware is held fixed, we show that this algorithmic design problem is NP-hard even for particularly simple classes of cost functions, confirming what many perhaps have suspected about this sort of design-time optimization. We also introduce a formalism, based on the notion of label maps, for the broader problem in which the design space encompasses choices for both actuation and sensin
We address problems underlying the algorithmic question of automating the co-design of robot hardware in tandem with its apposite software. Specifically, we consider the impact that degradations of a robot’s sensor and actuation suites may have on the ability of that robot to complete its tasks. Expanding upon prior work that addresses similar questions in the context of filtering, we introduce a new formal structure that generalizes and consolidates a variety of well known structures including many forms of plans, planning problems, and filters, into a single data structure called a procrustean graph. We describe a collection of operations on procrustean graphs (both semantics-preserving and semantics-mutating), and show how a family of
We address problems underlying the algorithmic question of automating the co-design of robot hardware in tandem with its apposite software. Specifically, we consider the impact that degradations of a robot’s sensor and actuation suites may have on the ability of that robot to complete its tasks. We introduce a new formal structure that generalizes and consolidates a variety of well-known structures including many forms of plans, planning problems, and filters, into a single data structure called a procrustean graph, and give these graph structures semantics in terms of ideas based in formal language theory. We describe a collection of operations on procrustean graphs (both semantics-preserving and semantics-mutating), and show how a famil
Assuming one wants to design the most cost-effective robot for some task, how difficult is it to choose the robot’s actuators? This paper addresses that question in algorithmic terms, considering the problem of identifying optimal sets of actuation capabilities to allow a robot to complete a given task. We consider various cost functions which model the cost needed to equip a robot with some capabilities, and show that the general form of this problem is NP-hard, confirming what many perhaps have suspected about this sort of design-time optimization. As a result, several questions of interest having both optimality and efficiency of solution is unlikely. However, we also show that, for some specific types of cost functions, the problem i
We wish to minimize the information that a robot maintains to carry out its task. Filters are one way to keep stored state consistent with sensed values, though they may also capture some information about the structure of the world that the robot inhabits. This paper builds on prior work on (improper) filter minimization, but considers a new way to characterize structure in the world. By introducing a probabilistic model, one can define a notion of expected distance between two filters. Then, with such a measure, we pose the question of optimal lossy compression in the sense of having minimal expected distance. The problem retains the NP-hardness of the non-probabilistic worst-case minimization and, consequently, in this paper we focus on
Recent research in algorithmic robotics considers combinatorial filters, which concisely capture the discrete structure underlying many reasoning problems for robots. An important recent result is that the filter minimization problem—Given a filter, find the smallest equivalent filter—is NP-hard. This paper extends that result along several dimensions, including hardness proofs for some natural special cases and for approximation, and new results analyzing the only known algorithm for this problem. We show that this problem is not fixed-parameter tractable for any of the obvious parameters, but it is fixed-parameter tractable for a certain combination of new parameters.
Combinatorial filters have been the subject of increasing interest from the robotics community in recent years. This paper considers automatic reduction of combinatorial filters to a given size, even if that reduction necessitates changes to the filter's behavior. We introduce an algorithmic problem called improper filter reduction, in which the input is a combinatorial filter F along with an integer k representing the target size. The output is another combinatorial filter F'with at most k states, such that the difference in behavior between F and F'is minimal. We present two metrics for measuring the distance between pairs of filters, describe dynamic programming algorithms for computing these distances, and show that improper filter redu
For a given robot and a given task, this paper addresses questions about which modifications may be made to the robot’s suite of sensors without impacting the robot’s behavior in completing its task. Though this is an important design-time question, few principled methods exist for providing a definitive answer in general. Utilizing and extending the language of combinatorial filters, this paper aims to fill that lacuna by introducing theoretical tools for reasoning about sensors and representations of sensors. It introduces new representations for sensors and filters, exploring the relationship between those elements and the specific information needed to perform a task. It then shows how these tools can be used to algorithmically answ
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