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60th Anniversary Symposium of the International-Association-for-Shell-and-Spatial-Structures (IASS SYMPOSIUM) / 9th International Conference on Textile Composites and Inflatable Structures (STRUCTURAL MEMBRANES)

作者： Esposito, Lorenzo Boccia, Gaetano B. Luporino, Alessandro Pone, Sergio Univ Napoli Federico II DiARC Dipartimento Architettura Via Toledo 402 I-80134 Naples Italy

ISBN: (纸本)9788412110104

The study investigates the design and construction processes of masonry domes built without the use of centrings. In particular, it focuses on those built using a 'compass', i.e. an erection device that simplifies the construction process, and guarantees the bricklaying accuracy. The foundation of this research project can be found in the work of Fabrizio Carola (1931-2019) who used an erection method for masonry domes inspired by the 'Nubian vault technique'. The design and construction processes used by Carola have been analyzed with the aim of identifying a sequence of operations, which were then simulated in a digital environment by means of recursive algorithms. Finally, the study moved to the implementation of two bespoke designed contraptions for the design of non-spherical domes. The result of this study is a computational tool which can be used to design different typologies of centring-less masonry domes and simulate their construction process.

关键词： masonry domes centring-less domes computational morphogenesis recursive algorithms

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Language-based vectorization and parallelization using intrinsics, OpenMP, TBB and Cilk Plus

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JOURNAL OF SUPERCOMPUTING 2018年第4期74卷 1461-1472页

作者： Stpiczynski, Przemyslaw Marie Curie Sklodowska Univ Inst Math Pl Marii Curie Sklodowskiej 1 PL-20031 Lublin Poland

The aim of this paper is to evaluate OpenMP, TBB and Cilk Plus as basic language-based tools for simple and efficient parallelization of recursively defined computational problems and other problems that need both task and data parallelization techniques. We show how to use these models of parallel programming to transform a source code of Adaptive Simpson's Integration to programs that can utilize multiple cores of modern processors. Using the example of Belman-Ford algorithm for solving single-source shortest path problems, we advise how to improve performance of data parallel algorithms by tuning data structures for better utilization of vector extensions of modern processors. Manual vectorization techniques based on Cilk array notation and intrinsics are presented. We also show how to simplify such optimization using Intel SIMD Data Layout Template containers.

关键词： Multicore Manycore recursive algorithms Shortest path problems Intrinsics OpenMP Cilk Plus TBB SDLT containers

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Planning the Resource of Information Transmission for Connection Lines of Multiservice Hierarchical Access Networks

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AUTOMATION AND REMOTE CONTROL 2018年第8期79卷 1422-1433页

作者： Stepanov, S. N. Stepanov, M. S. Moscow Tech Univ Commun & Comp Sci Moscow Russia

We construct and investigate a mathematical model for joint servicing of real-time multiservice traffic in access networks with a hierarchical topology. The model takes into account how the arrival of claims in each flow depends on the number of users that form this flow of claims and that are being serviced. We define quality indicators for joint servicing of claims through the values of stationary probabilities in the model. We obtain relations between them that simplify their estimation. We develop an algorithm for calculating the characteristics of the model based on an implementation of the convolution algorithm. We propose a procedure for estimating the transmission rate of connecting lines in the access network needed to service incoming traffic with a given quality. We also give numerical examples that illustrate the characteristic features of implementing the developed computational procedures.

关键词： hierarchical access networks multiservice traffic Engset model system of equilibrium equations recursive algorithms transmission resource planning

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Screw and Lie group theory in multibody kinematics Motion representation and recursive kinematics of tree-topology systems

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MULTIBODY SYSTEM DYNAMICS 2018年第1期43卷 37-70页

作者： Mueller, Andreas Johannes Kepler Univ Linz Inst Robot Altenberger Str 69 A-4040 Linz Austria

After three decades of computational multibody system (MBS) dynamics, current research is centered at the development of compact and user-friendly yet computationally efficient formulations for the analysis of complex MBS. The key to this is a holistic geometric approach to the kinematics modeling observing that the general motion of rigid bodies and the relative motion due to technical joints are screw motions. Moreover, screw theory provides the geometric setting and Lie group theory the analytic foundation for an intuitive and compact MBS modeling. The inherent frame invariance of this modeling approach gives rise to very efficient recursive algorithms, for which the so-called "spatial operator algebra" is one example, and allows for use of readily available geometric data. In this paper, three variants for describing the configuration of tree-topology MBS in terms of relative coordinates, that is, joint variables, are presented: the standard formulation using body-fixed joint frames, a formulation without joint frames, and a formulation without either joint or body-fixed reference frames. This allows for describing the MBS kinematics without introducing joint reference frames and therewith rendering the use of restrictive modeling convention, such as Denavit-Hartenberg parameters, redundant. Four different definitions of twists are recalled, and the corresponding recursive expressions are derived. The corresponding Jacobians and their factorization are derived. The aim of this paper is to motivate the use of Lie group modeling and to provide a review of different formulations for the kinematics of tree-topology MBS in terms of relative (joint) coordinates from the unifying perspective of screw and Lie group theory.

关键词： Rigid bodies Multibody systems Kinematics Relative coordinates recursive algorithms Screws Lie groups Frame invariance

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Robot dynamics: A recursive algorithm for efficient calculation of Christoffel symbols

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MECHANISM AND MACHINE THEORY 2019年 142卷

作者： Safeea, Mohammad Neto, Pedro Bearee, Richard Univ Coimbra Dept Mech Engn P-3030788 Coimbra Portugal LISPEN Arts & Metiers F-59800 Lille France

Christoffel symbols of the first kind are very important in robot dynamics. They are used for tuning various proposed robot controllers, for determining the bounds on Coriolis/Centrifugal matrix, for mathematical formulation of optimal trajectory calculation, among others. In the literature of robot dynamics, Christoffel symbols of the first kind are calculated from Lagrangian dynamics using an off-line generated symbolic formula. In this study we present a novel and efficient recursive, non-symbolic, method where Christoffel symbols of the first kind are calculated on-the-fly based on the inertial parameters of robot's links and their transformation matrices. The proposed method was analyzed in terms of execution time, computational complexity and numerical error. Results show that the proposed algorithm compares favorably with existing methods. (C) 2019 Elsevier Ltd. All rights reserved.

关键词： Dynamicss Christoffel symbols recursive algorithms

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recursive Subspace-based Predictive Control and Its Application to Fault-tolerant Control

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IFAC-PapersOnLine 2018年第24期51卷 696-702页

作者： Gao, Jingjing Yang, Xu Li, Linlin Luo, Hao Ding, Steven X. Zhang, Kai Peng, Kaixiang School of Automation and Electrical Engineering University of Science and Technology Beijing Beijing100083 China School of Astronautics Harbin Institute of Technology Harbin150001 China Institute of Automatic Control and Complex Systems Faculty of Engineering University of Duisburg-Essen Duisburg47057 Germany

This paper investigates the data-driven realization of predictive controllers, and its application to fault-tolerant control. With the aid of subspace identification method, the subspace predictor is first derived in the closed-loop setup. To cope with the change in the process, a recursive algorithm is adopted to recursive update the subspace matrices. The data-driven predictive controller is designed by seeking the solution of the quadratic programming problem, without the information of the predesigned controller. Then, it is applied to fault-tolerant control by implementing the recursive subspace predictor. In the end, the effectiveness of the proposed method is verified by a case study on the three-tank system. © 2018

关键词： Controllers Fault tolerance Quadratic programming Fault tolerant control Predictive control Predictive controller Quadratic programming problems recursive algorithms Subspace identification methods Subspace predictors Three tank system

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Friction State Classification Based on Vehicle Inertial Measurements

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IFAC-PapersOnLine 2019年第5期52卷 72-77页

作者： Donald Selmanaj Matteo Corno Sergio M. Savaresi Department of Automation Polytechnic University of Tirana Sheshi “Nënë Tereza” Nr.4 Tirana Albania Dipartimento di Elettronica Informazione e Bioingegneria Politecnico di Milano Piazza L. da Vinci 32 20133 Milano Italy

Tire-road friction is the most important characteristic defining the planar dynamics of wheeled vehicles. It has consequences on the drivability, stability and tuning of the active vehicle dynamics control systems. This paper proposes two online friction estimation methods designed for the adaptation of vehicle dynamics control algorithms. The problem is framed as a classification problem where inertial measurements are used to discriminate between high and low friction regimes. The first method merges a recursive least-squares (RLS) algorithm with a heuristic bistable logic to classify the friction condition and promptly react to its changes. The second method runs a classification algorithm on the slip-acceleration characteristic. Both methods simultaneously account for the longitudinal and lateral dynamics and are tested on experimental data.

关键词： Friction Vehicles dynamics Classification recursive algorithms Nonlinear algorithms

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Introducing Compressed Mixture Models for Predicting Long-Lasting Brake Events

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IFAC-PapersOnLine 2018年第31期51卷 840-845页

作者： Emil, Staf Tomas, McKelvey Propulsion Controls & Calibration Volvo Cars Gothenburg41878 Sweden Electrical Engineering Chalmers University of Technology Gothenburg41258 Sweden

With tougher restrictions on emissions the automotive industry is in dire need of additional functionality to reduce emissions. We conduct a case study trying to predict long-lasting brake events, to support the decision-making process when the engine can beneficially be put to idle or shut down to achieve emission reduction. We introduce Compressed Mixture Models, a multivariate and mixed variate kernel density model featuring online training and complexity reduction, and use it for prediction purposes. The results show that the proposed method produces comparable prediction results as a Random Forest Classifier and outperform a Support Vector Classifier. On an urban road a prediction accuracy of 87.4 % is obtained, while a prediction accuracy of 76.4 % on a highway segment using the proposed method. Furthermore, it is possible to use a trained Compressed Mixture Model as a tool for statistical inference to study the properties of the observed realization of the underlying random variables. © 2018

关键词： Forecasting Automotive industry Brakes Decision making Decision trees Emission control Information theory Learning systems Mixtures Decision making process Model complexity Prediction methods Probabilistic models Random forest classifier recursive algorithms Statistical inference Support vector classifiers

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Efficient Language-Based Parallelization of Computational Problems Using Cilk Plus 12th

Efficient Language-Based Parallelization of Computational Pr...

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12th International Conference on Parallel Processing and Applied Mathematics (PPAM)

作者： Stpiczynski, Przemyslaw Marie Curie Sklodowska Univ Inst Math Pl Marii Curie Sklodowskiej 1 PL-20031 Lublin Poland

ISBN: (纸本)9783319780542;9783319780535

The aim of this paper is to evaluate Cilk Plus as a language-based tool for simple and efficient parallelization of recursively defined computational problems and other problems that need both task and data parallelization techniques. We show that existing source codes can be easily transformed to programs that can utilize multiple cores and additionally offload some computations to coprocessors like Intel Xeon Phi. We also advise how to improve simplicity and performance of data parallel algorithms by tuning data structures to utilize vector extensions of modern processors. Numerical experiments show that in most cases our Cilk Plus versions of Adaptive Simpson's Integration and BelmanFord Algorithm for solving single-source shortest-path problems achieve better performance than corresponding OpenMP programs.

关键词： Cilk Plus Multicore Xeon Phi Vectorization Offload recursive algorithms Shortest-path problems

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Hidden Markov Model Estimation-Based Q-learning for Partially Observable Markov Decision Process

Hidden Markov Model Estimation-Based Q-learning for Partiall...

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American Control Conference

作者： Hyung-Jin Yoon Donghwan Lee Naira Hovakimyan University of Illinois at Urbana-Champaign (UIUC) Urbana IL 61801 USA UIUC

ISBN: (纸本)9781538679012;9781538679265

The objective is to study an on-line Hidden Markov model (HMM) estimation-based Q-learning algorithm for partially observable Markov decision process (POMDP) on finite state and action sets. When the full state observation is available, Q-learning finds the optimal action-value function given the current action (Q-function). However, Q-learning can perform poorly when the full state observation is not available. In this paper, we formulate the POMDP estimation into a HMM estimation problem and propose a recursive algorithm to estimate both the POMDP parameter and Q-function concurrently. Also, we show that the POMDP estimation converges to a set of stationary points for the maximum likelihood estimate, and the Q-function estimation converges to a fixed point that satisfies the Bellman optimality equation weighted on the invariant distribution of the state belief determined by the HMM estimation process.

关键词： hidden Markov models learning (artificial intelligence) maximum likelihood estimation optimisation Hidden Markov models maximum likelihood estimation Markov chain Q FUNCTIONS recursive algorithms

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