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Mechanical linkage design and NP-hardness

MECHANISM AND MACHINE THEORY 2014年 82卷 97-114页

作者： Lieutier, Andre Rameau, Jean-Francois Dassault Syst F-78140 Velizy Villacoublay France LISMMA F-91407 St Ouen France

We prove the NP-hardness of two fundamental problems in mechanism design. Given a set of rigid parts and prescribed joints, the first problem consists in deciding whether there exists an assembly of these parts matching the link constraints. Given a set of rigid parts and prescribed joints with parameterized dimensions, the second problem consists in deciding if there exists some dimensioning making the assembly mobile. The proof of hardness makes use of a reduction from Partition Problem for the first problem and from 3SAT for the second one. (C) 2014 Elsevier Ltd. All rights reserved.

关键词： Dimensioning Assembly Mobility algorithmic complexity NP-hard

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Guest editorial-Uncertainty and parameter space analysis in visualization

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COMPUTERS & GRAPHICS-UK 2014年第Jun.期41卷 A1-A2页

作者： Heinzl, Christoph Bruckner, Stefan Groeller, Eduard Univ Appl Sci Upper Austria Linz Austria Univ Bergen N-5020 Bergen Norway Vienna Univ Technol Inst Comp Graph & Algorithms Vienna Austria

Uncertainty and parameter space analysis in visualization are becoming increasingly prevalent and play an important role in astronomical, (bio)-medical, industrial, and engineering applications. All these areas require methods and techniques which help domain specialists to understand the processes involved in data generation, the reliability of the data, and the distribution of and reasons for uncertainty. Furthermore, with increasing algorithmic complexity additional the following questions arise: 1. How does a slight parameter change modify the result? 2. How stable is a parameter? 3. In which range is a parameter stable? 4. Which parameter set is optimal for a specific problem?

关键词： reliability data Uncertainty Visualization Optimal Specialists data generation algorithmic complexity stalls(animals) methods and techniques parameter setting parameter space methods

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A continuous characterization of the maximum-edge biclique problem

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JOURNAL OF GLOBAL OPTIMIZATION 2014年第3期58卷 439-464页

作者： Gillis, Nicolas Glineur, Francois Catholic Univ Louvain ICTEAM Inst B-1348 Louvain Belgium Catholic Univ Louvain Ctr Operat Res & Econometr B-1348 Louvain Belgium

The problem of finding large complete subgraphs in bipartite graphs (that is, bicliques) is a well-known combinatorial optimization problem referred to as the maximum-edge biclique problem (MBP), and has many applications, e.g., in web community discovery, biological data analysis and text mining. In this paper, we present a new continuous characterization for MBP. Given a bipartite graph , we are able to formulate a continuous optimization problem (namely, an approximate rank-one matrix factorization problem with nonnegativity constraints, R1N for short), and show that there is a one-to-one correspondence between (1) the maximum (i.e., the largest) bicliques of and the global minima of R1N, and (2) the maximal bicliques of (i.e., bicliques not contained in any larger biclique) and the local minima of R1N. We also show that any stationary points of R1N must be close to a biclique of . This allows us to design a new type of biclique finding algorithm based on the application of a block-coordinate descent scheme to R1N. We show that this algorithm, whose algorithmic complexity per iteration is proportional to the number of edges in the graph, is guaranteed to converge to a biclique and that it performs competitively with existing methods on random graphs and text mining datasets. Finally, we show how R1N is closely related to the Motzkin-Strauss formalism for cliques.

关键词： Maximum-edge biclique problem Biclique finding algorithm algorithmic complexity Nonnegative rank-one approximation

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Analysis by synthesis spatial audio coding

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IET SIGNAL PROCESSING 2014年第1期8卷 30-38页

作者： Elfitri, Ikhwana Shi, Xiyu Kondoz, Ahmet Univ Surrey Lab Multimedia Commun Res Guildford GU2 7XH Surrey England Andalas Univ Fac Engn Dept Elect Engn Padang Indonesia Mulsys Ltd Guildford Surrey England

This study presents a novel spatial audio coding (SAC) technique, called analysis by synthesis SAC (AbS-SAC), with a capability of minimising signal distortion introduced during the encoding processes. The reverse one-to-two (R-OTT), a module applied in the MPEG Surround to down-mix two channels as a single channel, is first configured as a closed-loop system. This closed-loop module offers a capability to reduce the quantisation errors of the spatial parameters, leading to an improved quality of the synthesised audio signals. Moreover, a sub-optimal AbS optimisation, based on the closed-loop R-OTT module, is proposed. This algorithm addresses a problem of practicality in implementing an optimal AbS optimisation while it is still capable of improving further the quality of the reconstructed audio signals. In terms of algorithm complexity, the proposed sub-optimal algorithm provides scalability. The results of objective and subjective tests are presented. It is shown that significant improvement of the objective performance, when compared to the conventional open-loop approach, is achieved. On the other hand, subjective test show that the proposed technique achieves higher subjective difference grade scores than the tested advanced audio coding multichannel.

关键词： single-channel Signal distortion Subjective testing algorithmic complexity Audio coding audio signals

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Depth First Forwarding for Low Power and Lossy Networks: Application and Extension

Depth First Forwarding for Low Power and Lossy Networks: App...

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1st IEEE World Forum on Internet of Things (WF-IoT)

作者： Yi, Jiazi Clausen, Thomas Herberg, Ulrich Ecole Polytech Lab Informat LIX F-91128 Palaiseau France Fujitsu Labs Amer Sunnyvale CA USA

ISBN: (纸本)9781479934591

Data delivery across a multi-hop low-power and lossy networks (LLNs) is a challenging task: devices participating in such a network have strictly limited computational power and storage, and the communication channels are of low capacity, time-varying and with high loss rates. Consequently, routing protocols finding paths through such a network must be frugal in their control traffic and state requirements, as well as in algorithmic complexity - and even once paths have been found, these may be usable only intermittently, or for a very short time due to changes on the channel. Routing protocols exist for such networks, balancing reactivity to topology and channel variation with frugality in resource requirements. Complementary component to routing protocols for such LLNs exist, intended not to manage global topology, but to react rapidly to local data delivery failures and (attempt to) successfully deliver data while giving a routing protocol time to recover globally from such a failure. Specifically, this paper studies the "Depth-First Forwarding (DFF) in Unreliable Networks" protocol, standardised within the IETF in June 2013. Moreover, this paper proposes optimisations to that protocol, denoted DFF++, for improved performance and reactivity whilst remaining fully interoperable with DFF as standardised, and incurring neither additional data sets nor protocol signals to be generated.

关键词： performance evaluation routing protocols telecommunication channels telecommunication network topology telecommunication traffic algorithmic complexity channel variation communication channels control traffic depth first forwarding high loss rates limited computational power limited storage local data delivery failures multihop low-power-and-lossy networks path finding performance improvement reactivity balancing reactivity improvement resource requirements routing protocols state requirements topology variation unreliable networks protocol Internet Network topology Optimization Routing Routing protocols Unicast

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Efficient Gaussian Process modelling of section weights in polymer stretch blow moulding 10

Efficient Gaussian Process modelling of section weights in p...

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United-Kingdom-Automatic-Control-Council (UKACC) 10th International Conference on Control (CONTROL)

作者： Yan, Juan Li, Kang Deng, Jing Yang, Ziqi Queens Univ Belfast Sch Elect Elect Engn & Comp Sci Belfast Antrim North Ireland

ISBN: (纸本)9781479950119

The injection stretch blow moulding (ISBM) has been widely applied in polyethylene terephthalate bottles production process. The modelling of the blowing conditions is important for the control of the process. In this paper, a nonparametric modelling method namely Gaussian Process is employed and applied to estimate the section weights during the process. A key issue in Gaussian Process modelling is to iteratively compute the covariance matrix inversion which is often extremely time-consuming as the optimization of the Gaussian process requires to call the marginal likelihood function and its gradient function. The matrix decomposition methods like Cholesky and QR decomposition have shown to be able to significantly reduce the computation complexity in solving linear problems, and they are also used in Gaussian process modelling in computing the product of a matrix inversion with a column vector in this paper. The algorithm complexities are analysed and compared, and it is shown that the proposed method is particularly useful as the matrix size increases. The proposed method is then used to model the section weights in polymer stretch blow moulding, and the results confirm the efficiency of the proposed method in significantly reducing the computational effort.

关键词： Plastics-Blow molding column vector matrix inversion Likelihood Functions Gauss Modeling Stretch Cholesky Gaussian processes matrix decomposition algorithmic complexity Polyethylene Terephthalates polymers

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Data- and State-Dependent Power Characterisation and Simulation of Black-Box RTL IP Components at System Level 17

Data- and State-Dependent Power Characterisation and Simulat...

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17th Euromicro Conference on Digital System Design (DSD)

作者： Lorenz, Daniel Gruettner, Kim Nebel, Wolfgang OFFIS Inst Informat Technol D-26121 Oldenburg Germany Carl von Ossietzky Univ Oldenburg D-26121 Oldenburg Germany

ISBN: (纸本)9781479957934

Due to the increasing algorithmic complexity of todays embedded systems, the consideration of extra-functional properties becomes even more important. Extra-functional properties such as timing, power consumption, and temperature need to be validated against given requirements on all abstraction levels. For timing and power consumption at RT- and gate-level, several techniques are available, but there is still a lack of methods and tools for power estimation and analyses at electronic system level (ESL) and above. Existing ESL methods in most cases use state-based methods for power simulation. This may lead to inaccurate results, especially for data-dependent designs. In this paper, we extend the Power State Machine (PSM) model for black-box RTL IP components with a mechanism that employs data-dependent switching activity using the Hamming distance (HD). In pipelined designs, we do not only consider the input HD but also the HDs of the internal pipeline stage registers. Since these registers of black-box IP are not observable from the outside, our model derives the internal HDs from previous input data. The results show that our extension achieves up to 38% better results than the previous PSM approach and up to 35% better results compared to a model considering only the input HD.

关键词： Clocks Energy consumption High definition video Pipelines Power demand Registers Switches Data-dependent Power Electronic System Level Power Characterisation Power Simulation Power State Machine State-dependent Power System Level Power Registers system level high definition video Power demand pipeline Timing devices Switches energy consumption Resistor Transistor Logic HD EIS IMPLEMENTATION PLANS piping power estimation algorithmic complexity simulating

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Multicriteria Approaches for Predictive Model Generation: A Comparative Experimental Study

Multicriteria Approaches for Predictive Model Generation: A ...

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2014 IEEE Symposium on Computational Intelligence in Multi-Criteria Decision-Making (MCDM)

作者： Al-Jubouri, Bassma Gabrys, Bogdan Bournemouth Univ Fac Sci & Technol Smart Technol Res Ctr Poole BH12 5BB Dorset England

ISBN: (纸本)9781479944675

This study investigates the evaluation of machine learning models based on multiple criteria. The criteria included are: predictive model accuracy, model complexity, and algorithmic complexity (related to the learning/adaptation algorithm and prediction delivery) captured by monitoring the execution time. Furthermore, it compares the models generated from optimising the criteria using two approaches. The first approach is a scalarized multi objective optimisation, where the models are generated from optimising a single cost function that combines the criteria. On the other hand the second approach uses a Pareto-based multi objective optimisation to trade-off the three criteria and to generate a set of non-dominated models. This study shows that defining universal measures for the three criteria is not always feasible. Furthermore, it was shown that, the models generated from Pareto-based multi objective optimisation approach can be more accurate and more diverse than the models generated from scalarized multi objective optimisation approach.

关键词： Pareto optimisation computational complexity learning (artificial intelligence) prediction theory Pareto-based multiobjective optimisation adaptation algorithm algorithmic complexity learning algorithm machine learning models model complexity multicriteria approaches multiple criteria nondominated models prediction delivery predictive model accuracy predictive model generation scalarized multiobjective optimisation Accuracy Artificial neural networks complexity theory Mathematical model Optimization Prediction algorithms Predictive models Pareto optimisation algorithmic complexity Prediction theory Prediction algorithms complexity theory learning algorithms Prediction models Artificial neural networks complexity classes Mathematical Model machine model Multiple objective

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Path Planning for Robot Using Population-Based Incremental Learning 4

Path Planning for Robot Using Population-Based Incremental L...

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4th IEEE Annual International Conference on Cyber Technology in Automation, Control, and Intelligent Systems (CYBER)

作者： Xu, Miao Lee, Jaesung Bahn, Sang-Kyu Kang, Bo-Yeong Kyungpook Natl Univ Sch Mech Engn Daegu South Korea Chung Ang Univ Sch Comp Sci & Engn Seoul 156756 South Korea

ISBN: (纸本)9781479936694

Recently, genetic algorithms (GAs) have attracted great interest owing to efficiency and flexibility against complex robot path planning problems. To accelerate the convergence speed, preceding researches adapted conventional GAs by using problem-specific techniques. However, such approaches increase computational burden and algorithmic complexity, resulting in subsequent additional problems. In this paper, we used Population-Based Incremental Learning (PBIL) algorithm for robot path planning as a probabilistic evolutionary approach. In addition to PBIL, we also proposed the probabilistic model of nodes and the edge bank to generate promising paths. The experimental results demonstrate that the proposed method gave markedly better performance than its conventional counterparts (GA,kGA,fGA) in terms of success rates and the quality of obtained paths.

关键词： Convergence Genetic algorithms Maintenance engineering Mathematical model Path planning Robots Safety Path planning Robot Maintenance engineering Genetic Algorithm (GA) Mathematical Model Converge Consumer safety safety learning (artificial intelligence) conventional gas algorithmic complexity Probabilistic Model

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algorithmic complexity of FDTD and Ray Tracing method for indoor propagation modeling

Algorithmic complexity of FDTD and Ray Tracing method for in...

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European Conference on Antennas and Propagation

作者： Lajos Nagy Robert Dady Andrea Farkasvolgyi Department of Broadband Infocommunications and Electromagnetic Theory Budapest University of Technology and Economics

ISBN: (纸本)9781424447534

Growing interest in providing and improving radio coverage for mobile phones and wireless LANs inside buildings has recently emerged. The need of such coverage appears mainly in office buildings, shopping malls in very complex environment. Although the three dimensional FDTD method has shown great promise, the calculation time is very environment dependent and exceeds the calculation time of ray tracing or ray launching in most cases. In this article, we focus on the theoretical estimation and comparison of FDTD and ray methods in aspects of the algorithmic complexity.

关键词： algorithmic complexity computational time Ray tracing radio coverage Tracer techniques Buildings wireless local area network (WLAN) Mobile phones Half line Ray RAYS built structure

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