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Article
Publication date: 18 January 2016

Huajun Liu, Cailing Wang and Jingyu Yang

– This paper aims to present a novel scheme of multiple vanishing points (VPs) estimation and corresponding lanes identification.

Abstract

Purpose

This paper aims to present a novel scheme of multiple vanishing points (VPs) estimation and corresponding lanes identification.

Design/methodology/approach

The scheme proposed here includes two main stages: VPs estimation and lane identification. VPs estimation based on vanishing direction hypothesis and Bayesian posterior probability estimation in the image Hough space is a foremost contribution, and then VPs are estimated through an optimal objective function. In lane identification stage, the selected linear samples supervised by estimated VPs are clustered based on the gradient direction of linear features to separate lanes, and finally all the lanes are identified through an identification function.

Findings

The scheme and algorithms are tested on real data sets collected from an intelligent vehicle. It is more efficient and more accurate than recent similar methods for structured road, and especially multiple VPs identification and estimation of branch road can be achieved and lanes of branch road can be identified for complex scenarios based on Bayesian posterior probability verification framework. Experimental results demonstrate VPs, and lanes are practical for challenging structured and semi-structured complex road scenarios.

Originality/value

A Bayesian posterior probability verification framework is proposed to estimate multiple VPs and corresponding lanes for road scene understanding of structured or semi-structured road monocular images on intelligent vehicles.

Details

Industrial Robot: An International Journal, vol. 43 no. 1
Type: Research Article
ISSN: 0143-991X

Keywords

Article
Publication date: 8 June 2020

Zhe Wang, Xisheng Li, Xiaojuan Zhang, Yanru Bai and Chengcai Zheng

The purpose of this study is to use visual and inertial sensors to achieve real-time location. How to provide an accurate location has become a popular research topic in…

Abstract

Purpose

The purpose of this study is to use visual and inertial sensors to achieve real-time location. How to provide an accurate location has become a popular research topic in the field of indoor navigation. Although the complementarity of vision and inertia has been widely applied in indoor navigation, many problems remain, such as inertial sensor deviation calibration, unsynchronized visual and inertial data acquisition and large amount of stored data.

Design/methodology/approach

First, this study demonstrates that the vanishing point (VP) evaluation function improves the precision of extraction, and the nearest ground corner point (NGCP) of the adjacent frame is estimated by pre-integrating the inertial sensor. The Sequential Similarity Detection Algorithm (SSDA) and Random Sample Consensus (RANSAC) algorithms are adopted to accurately match the adjacent NGCP in the estimated region of interest. Second, the model of visual pose is established by using the parameters of the camera itself, VP and NGCP. The model of inertial pose is established by pre-integrating. Third, location is calculated by fusing the model of vision and inertia.

Findings

In this paper, a novel method is proposed to fuse visual and inertial sensor to locate indoor environment. The authors describe the building of an embedded hardware platform to the best of their knowledge and compare the result with a mature method and POSAV310.

Originality/value

This paper proposes a VP evaluation function that is used to extract the most advantages in the intersection of a plurality of parallel lines. To improve the extraction speed of adjacent frame, the authors first proposed fusing the NGCP of the current frame and the calibrated pre-integration to estimate the NGCP of the next frame. The visual pose model was established using extinction VP and NGCP, calibration of inertial sensor. This theory offers the linear processing equation of gyroscope and accelerometer by the model of visual and inertial pose.

Article
Publication date: 1 February 2006

Dragan D. Milasinovic

The paper deals with the rheological‐dynamical analogy in which the three‐dimensional stress‐strain relations are defined under cyclic variation of stress for Hencky’s…

Abstract

The paper deals with the rheological‐dynamical analogy in which the three‐dimensional stress‐strain relations are defined under cyclic variation of stress for Hencky’s total strain theory. In many practical visco‐elasto‐plastic problems, like as multiaxial fatigue under loading at constant stress amplitude and constant stress ratio, the load‐carrying members are subjected to proportional loading. The classical Hencky’s theory has the advantage of mathematical convenience but its disadvantage is that the deformations predicted for the volume element are independent of the loading path. The existing formulations of the constitutive models for metals are mainly based on the Prandtl‐Reuss incremental theory of elasto‐plasticity, slip theory of plasticity or continuum damage mechanics. They have been shown capable of reproducing satisfactorily most experimental results available for metallic specimens. However, from the theoretical viewpoint little has been said about how these formulations relate to realistic predicting many different inelastic and time dependent problems of two‐ or threedimensional solids, such as fatigue, discontinuous plastic deformation etc. In this paper, fundamentally new aspect of isochronous constitutive relations for Hencky’s theory, which are dependent of the each loading path, is achieved by systematically introducing RDA concept into the continuum framework. Specific inelastic and fatigue formulation of triaxial state of stress is developed and discussed within the new theoretical tool and related to von Mises plasticity..

Details

Multidiscipline Modeling in Materials and Structures, vol. 2 no. 2
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 19 February 2020

Seishiro Matsubara, Kenjiro Terada, Ryusei Maeda, Takaya Kobayashi, Masanobu Murata, Takuya Sumiyama, Kenji Furuichi and Chisato Nonomura

This study aims to propose a novel viscoelastic–viscoplastic combined constitutive model for glassy amorphous polymers within the framework of thermodynamics at finite…

Abstract

Purpose

This study aims to propose a novel viscoelastic–viscoplastic combined constitutive model for glassy amorphous polymers within the framework of thermodynamics at finite strain that is capable of capturing their rate-dependent inelastic mechanical behavior in wide ranges of deformation rate and amount.

Design/methodology/approach

The rheology model whose viscoelastic and viscoplastic elements are connected in series is set in accordance with the multi-mechanism theory. Then, the constitutive functions are formulated on the basis of the multiplicative decomposition of the deformation gradient implicated by the rheology model within the framework of thermodynamics. Dynamic mechanical analysis (DMA) and loading/unloading/no-load tests for polycarbonate (PC) are conducted to identify the material parameters and demonstrate the capability of the proposed model.

Findings

The performance was validated in comparison with the series of the test results with different rates and amounts of deformation before unloading together. It has been confirmed that the proposed model can accommodate various material behaviors empirically observed, such as rate-dependent elasticity, elastic hysteresis, strain softening, orientation hardening and strain recovery.

Originality/value

This paper presents a novel rheological constitutive model in which the viscoelastic element connected in series with the viscoplastic one exclusively represents the elastic behavior, and each material response is formulated according to the multiplicatively decomposed deformation gradients. In particular, the yield strength followed by the isotropic hardening reflects the relaxation characteristics in the viscoelastic constitutive functions so that the glass transition temperature could be variant within the wide range of deformation rate. Consequently, the model enables us to properly represent the loading process up to large deformation regime followed by unloading and no-load processes.

Details

Engineering Computations, vol. 37 no. 5
Type: Research Article
ISSN: 0264-4401

Keywords

Book part
Publication date: 30 November 2017

Dennis Jancsary, Renate E. Meyer, Markus A. Höllerer and Eva Boxenbaum

In this article, we develop and advance an understanding of institutions as multimodal accomplishments. We draw on social semiotics and the linguistic concept of…

Abstract

In this article, we develop and advance an understanding of institutions as multimodal accomplishments. We draw on social semiotics and the linguistic concept of metafunctions to establish the visual as a specific mode of meaning construction. In addition, we make semiotic modes conducive to institutional inquiry by introducing the notion of distinct “modal registers” – specialized configurations of linguistic signs within a particular mode that are adapted and applied in the reproduction of institutions or institutional domains. At the core of our article, we operationalize metafunctions to develop methodology for the analysis of visual registers. We illustrate our approach with data from Corporate Social Responsibility (CSR) reporting in Austria.

Article
Publication date: 1 June 1996

Elie Bernard‐Weil and F. Mikol

Agonistic antagonistic system theory and praxis were born in the medical field, but may be defined now from an epistemological and biomathematical point of view. Describes…

Abstract

Agonistic antagonistic system theory and praxis were born in the medical field, but may be defined now from an epistemological and biomathematical point of view. Describes new developments in agonistic antagonistic (AA) theory and presents new applications. These include new mathematical approaches that involve variable parameters and partial derivatives in models for the regulation of AA couples (MRAAC). Gives new biomedical applications and, in explanation, a mechanism called “pathological homeostasis” (PH) is introduced. Also provides details of therapeutical trials. Suggests systems science or cybernetical strategies which are likely to have a broad field of application, particularly among decision makers in general.

Details

Kybernetes, vol. 25 no. 4
Type: Research Article
ISSN: 0368-492X

Keywords

Article
Publication date: 1 February 2006

Marinella Giunta and Aurora Angela Pisano

This paper proposes a new visco‐elastoplastic constitutive model for asphalt concretes able to reproduce the non linear time‐dependent behaviour of such materials.The…

Abstract

This paper proposes a new visco‐elastoplastic constitutive model for asphalt concretes able to reproduce the non linear time‐dependent behaviour of such materials.The constitutive model has been developed with the aim of making it fit specific experimental features previously observed. Moreover the proposed formulation will be demonstrated to be fully consistent with general thermodynamic requirements. Apart from a rigorous analytical formulation; a corresponding rheological sketch of the model is also given. From this representation, it can be shown that the model is essentially a combination of a generalized Maxwell model and a hardening visco‐plastic element.

Details

Multidiscipline Modeling in Materials and Structures, vol. 2 no. 2
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 9 August 2011

Vahid Vahdat Zad

Geometry, as the visual depiction of mathematics, has always comprised a major communicative language in architecture. Thus, geometry has traditionally been taught in…

Abstract

Purpose

Geometry, as the visual depiction of mathematics, has always comprised a major communicative language in architecture. Thus, geometry has traditionally been taught in architectural education to produce the perspective view of spaces from plans and elevations. This process is understood as a move from the actual to the abstract. The purpose of this paper is to show how the author has applied the geometry of perspective backwards to generate, from photos, the 3D reconstruction of a space that no longer exists.

Design/methodology/approach

What are the original form and the morphological evolution of Amir‐Chakhmagh Square? To address this question, the author processed photos of the square through geometric simulation. After verifying that the photos are taken from the same square, the author developed a geometrical reconstruction process to come up with the plan and elevations of the spaces, which is enough to reconstruct the 3D model. Finally, by virtue of these documents, the author analyzed the historical evolution of the square.

Findings

The main contribution of this research is recreating the architectural plans of the square, as well as introducing a simple method to extract plans and elevations from a given perspective.

Originality/value

The case study presented is the Amir‐Chakhmagh Square in the historic core of Yazd‐Iran. This square with an adjacent bazaar is one of the most important urban spaces of Iran, and was partially demolished in the modernizations of the 1920s. The need to renovate the remains of the square has called for new attempts to understand its original form.

Details

Kybernetes, vol. 40 no. 7/8
Type: Research Article
ISSN: 0368-492X

Keywords

Article
Publication date: 1 July 2005

Guillaume Hervé, Fabrice Gatuingt and Adnan Ibrahimbegović

To provide an efficient and robust constitutive equations for concrete ion application to high rate dynamics.

1064

Abstract

Purpose

To provide an efficient and robust constitutive equations for concrete ion application to high rate dynamics.

Design/methodology/approach

Develops an explicit‐implicit integration scheme for a concrete model. This robust integration scheme ensures computational efficiency. Comparison between simulations of impact of equivalent aircraft engine projectiles and the tests carried out in Sandia laboratory also demonstrate its efficiency.

Findings

Shows that modeling transient high rate dynamic behavior of concrete is very important to take into account for design concrete structures in the cases of dynamic loading conditions, such as an impact on the structure.

Originality/value

Proposes an original integration scheme for a coupled rate dependent damage plasticity model. Also provides a detailed consideration of the numerical stability of this kind of scheme for rate‐dependent damage model.

Details

Engineering Computations, vol. 22 no. 5/6
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 1 February 2009

Rajneesh Kumar and Geeta Partap

The propagation of free vibrations in microstretch thermoelastic homogeneous isotropic, thermally conducting plate bordered with layers of inviscid liquid on both sides…

Abstract

The propagation of free vibrations in microstretch thermoelastic homogeneous isotropic, thermally conducting plate bordered with layers of inviscid liquid on both sides subjected to stress free thermally insulated and isothermal conditions is investigated in the context of Lord and Shulman (L‐S) and Green and Lindsay (G‐L) theories of thermoelasticity. The secular equations for symmetric and skewsymmetric wave mode propagation are derived. The regions of secular equations are obtained and short wavelength waves of the secular equations are also discussed. At short wavelength limits, the secular equations reduce to Rayleigh surface wave frequency equations. Finally, the numerical solution is carried out for magnesium crystal composite material plate bordered with water. The dispersion curves for symmetric and skew‐symmetric wave modes are computed numerically and presented graphically.

Details

Multidiscipline Modeling in Materials and Structures, vol. 5 no. 2
Type: Research Article
ISSN: 1573-6105

Keywords

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