Causality in constraint propagation

1997 ◽  
Vol 11 (5) ◽  
pp. 419-433 ◽  
Author(s):  
Walid E. Habib ◽  
Allen C. Ward
Keyword(s):  
Physical System ◽  
Predicate Logic ◽  
Constraint Propagation ◽  
Design Rules ◽  
System Parameters ◽  
Causality Information ◽  
Propagation Rules ◽  
Account Variation

AbstractThis paper defines, for use in design, rules for propagating “distribution constraints” through relationships such as algebraic or vector equations. Distribution constraints are predicate logic statements about the values that physical system parameters may assume. The propagation rules take into account “variation source causality”: information about when and how the values are assigned during the design, manufacturing, and operation of the system.

scholarly journals Schedulers and redundancy for a class of constraint propagation rules

2005 ◽  
Vol 5 (4-5) ◽  
pp. 441-465 ◽  
Author(s):  
SEBASTIAN BRAND ◽  
KRZYSZTOF R. APT
Keyword(s):  
Constraint Programming ◽  
Constraint Propagation ◽  
Iteration Algorithm ◽  
Rule Based ◽  
Propagation Rules

We study here schedulers for a class of rules that naturally arise in the context of rule-based constraint programming. We systematically derive a scheduler for them from a generic iteration algorithm of Apt (2000). We apply this study to so-called membership rules of Apt and Monfroy (2001). This leads to an implementation that yields a considerably better performance for these rules than their execution as standard CHR rules. Finally, we show how redundant rules can be identified and how appropriately reduced sets of rules can be computed.

scholarly journals Simpler and Faster Algorithm for Checking the Dynamic Consistency of Conditional Simple Temporal Networks

2018 ◽  
Author(s):  
Luke Hunsberger ◽  
Roberto Posenato
Keyword(s):  
Recent Work ◽  
Constraint Propagation ◽  
Dynamic Consistency ◽  
Temporal Networks ◽  
Alternative Semantics ◽  
Open Questions ◽  
Simpler Algorithm ◽  
Simple Temporal Networks ◽  
Propagation Rules

Recent work on Conditional Simple Temporal Networks (CSTNs) has focused on checking the dynamic consistency (DC) property assuming that execution strategies can react instantaneously to observations. Three alternative semantics---IR-DC, 0-DC, and π-DC---have been presented. The most practical DC-checking algorithm for CSTNs has only been analyzed with respect to the IR-DC semantics, while the 0-DC semantics was shown to have a serious flaw that the π-DC semantics fixed. Whether the IR-DC semantics had the same flaw and, if so, what the consequences would be for the DC-checking algorithm remained open questions. This paper (1) shows that the IR-DC semantics is also flawed; (2) shows that one of the constraint-propagation rules from the IR-DC-checking algorithm is not sound with respect to the IR-DC semantics; (3) presents a simpler algorithm, called the π-DC-checking algorithm; (4) proves that it is sound and complete with respect to the π-DC semantics; and (5) empirically evaluates the new algorithm.

scholarly journals Huygens’ clocks revisited

2017 ◽  
Vol 4 (9) ◽  
pp. 170777 ◽  
Author(s):  
Allan R. Willms ◽  
Petko M. Kitanov ◽  
William F. Langford
Keyword(s):  
Normal Form ◽  
Physical System ◽  
Bifurcation Theory ◽  
Phase Synchronization ◽  
Unified Framework ◽  
System Parameters ◽  
Experimental Systems ◽  
Weakly Coupled ◽  
Equivariant Bifurcation Theory ◽  
Phase Motion

In 1665, Huygens observed that two identical pendulum clocks, weakly coupled through a heavy beam, soon synchronized with the same period and amplitude but with the two pendula swinging in opposite directions. This behaviour is now called anti-phase synchronization. This paper presents an analysis of the behaviour of a large class of coupled identical oscillators, including Huygens' clocks, using methods of equivariant bifurcation theory. The equivariant normal form for such systems is developed and the possible solutions are characterized. The transformation of the physical system parameters to the normal form parameters is given explicitly and applied to the physical values appropriate for Huygens' clocks, and to those of more recent studies. It is shown that Huygens' physical system could only exhibit anti-phase motion, explaining why Huygens observed exclusively this. By contrast, some more recent researchers have observed in-phase or other more complicated motion in their own experimental systems. Here, it is explained which physical characteristics of these systems allow for the existence of these other types of stable solutions. The present analysis not only accounts for these previously observed solutions in a unified framework, but also introduces behaviour not classified by other authors, such as a synchronized toroidal breather and a chaotic toroidal breather.

A logic-based framework for collection/item metadata relationships

2018 ◽  
Vol 74 (6) ◽  
pp. 1175-1189 ◽  
Author(s):  
Karen Wickett
Keyword(s):  
Knowledge Representation ◽  
Predicate Logic ◽  
Logical Form ◽  
Inference Rules ◽  
Content Type ◽  
First Order ◽  
Item Level ◽  
Potential Applications ◽  
Propagation Rules ◽  
Collection Level

Purpose The purpose of this paper is to present a framework for the articulation of relationships between collection-level and item-level metadata as logical inference rules. The framework is intended to allow the systematic generation of relevant propagation rules and to enable the assessment of those rules for particular contexts and the translation of rules into algorithmic processes. Design/methodology/approach The framework was developed using first order predicate logic. Relationships between collection-level and item-level description are expressed as propagation rules – inference rules where the properties of one entity entail conclusions about another entity in virtue of a particular relationship those individuals bear to each other. Propagation rules for reasoning between the collection and item level are grouped together in the framework according to their logical form as determined by the nature of the propagation action and the attributes involved in the rule. Findings The primary findings are the analysis of relationships between collection-level and item-level metadata, and the framework of categories of propagation rules. In order to fully develop the framework, the paper includes an analysis of colloquial metadata records and the collection membership relation that provides a general method for the translation of metadata records into formal knowledge representation languages. Originality/value The method for formalizing metadata records described in the paper represents significant progress in the application of knowledge representation techniques to problems of metadata creation and management, providing a flexible technique for encoding colloquial metadata as a set of statements in first-order logic. The framework of rules for collection/item metadata relationships has a range of potential applications for the enhancement or metadata systems and vocabularies.

Estimating Dynamics On-the-Fly Using Monocular Video

2011 ◽  
Author(s):  
Priyanshu Agarwal ◽  
Suren Kumar ◽  
Jason J. Corso ◽  
Venkat Krovi
Keyword(s):  
Physical System ◽  
Sequential Optimization ◽  
Physical Parameters ◽  
Double Pendulum ◽  
Equivalent System ◽  
Pendulum System ◽  
System Parameters ◽  
Optimization Framework ◽  
Video Images ◽  
Monocular Image

We present an optimization framework to help estimate on-the-fly both the motion and physical parameters of an articulated multibody system using uncalibrated monocular image sequences. The algorithm takes video images of a physical system as input and estimates the motion together with the physical system parameters, given only the underlying articulated model topology. A valid initial pose of the system is found using a sequential optimization framework and used to bootstrap the successive pose estimation as well as estimation of physical system parameters (kinematic/geometric lengths as well as mass, inertia, damping coefficients). We also address the issue of robustly estimating a dynamically-equivalent system using partial state information (solely from noisy visual observations) and without explicit inertial parameter information. This framework results in a robust dynamically-equivalent system with good predictive capabilities when tested on a double pendulum system.

scholarly journals TIPOLOGI RUMAH VERNAKULAR BERDASARKAN SISTEM FISIK DI KAMPUNG BANDAR PEKANBARU, RIAU

2020 ◽  
Vol 4 (3) ◽  
pp. 285
Author(s):  
Laili Dwi Annisa ◽  
Atiek Suprapti ◽  
Edward Edrianto Pandelaki
Keyword(s):  
Qualitative Methods ◽  
Physical System ◽  
Positive Impact ◽  
System Parameters ◽  
The Government ◽  
Physical Elements ◽  
The City

The development of the city of Pekanbaru originally came from a small hamlet on the edge of the Siak river. The development of Senapelan (Kampung Bandar now) is very closely related to the development of the Sri Indrapura Siak Kingdom which brought Malay culture and architecture to Bandar Village. To learn the characteristics of an architectural building one of them can be known by studying the typology of the building. Likewise with the characteristics of houses in a settlement, this can be known by examining the typology of the houses. The purpose of this study was to determine the typology of vernacular houses based on physical elements in Kampung Bandar Pekanbaru. The typology of this house will be discussed descriptively with qualitative methods. In this study, a strategy to determine the typology of vernacular houses uses physical system parameters that will discuss typologies based on the character of the material, typologies based on space constraints and typologies based on the structure of the house. The results of the study are expected to be a foundation for maintaining and preserving vernacular houses with Malay architecture in Pekanbaru. It also can be an input for the government to be able to develop the Bandar village area by continuing to emphasize the character of Malay architecture and advanced steps such as conservation so that it can be a positive impact on the city of Pekanbaru.

Simulation of Contact Bouncing Behavior in Starter Solenoid and Exploring Potential Feasible Solution

2013 ◽  
Vol 367 ◽  
pp. 204-208
Author(s):  
Nithesh Naik ◽  
Chandrasekhar Bhat ◽  
Pallanti Rao ◽  
J. Christopher ◽  
Faber Saldanha ◽  
...  
Keyword(s):  
Electromagnetic Force ◽  
Physical System ◽  
Feasible Solution ◽  
Measured Data ◽  
Generalized Model ◽  
Simulation Methodology ◽  
System Parameters ◽  
Model Based ◽  
Cost Constraints ◽  
Optimum Response

In this paper, investigation on starter solenoid to develop a generalized model based simulation methodology to simulate contact bounce characteristics and tuning of the parameters to reduce or eliminate the contact bounce in existing solenoids complying with all functional and cost constraints. Using the measured data, a generalized model based simulation methodology is built using Matlab Simulink to establish contact bouncing characteristics, which is highly non-linear in nature, under various conditions/parametric variations like electromagnetic force, air gap, hard stops, spring rate and mass. The simulation model reveals that the contact bounce is reduced to zero when the stiffness of the spindle spring is in the range of 1050 N/m to 1250 N/m. Thus we can conclude that the methodology adopted helps in understanding the characteristics of existing solenoids and providing practical suggestions for potential feasible modifications that can be incorporated in the existing solenoids so as to tune their physical system parameters for an optimum response.

Sign in / Sign up

Export Citation Format

Share Document