scholarly journals Extraction of the deterministic ingredient of a dynamic geodetic control network

2012 ◽  
Vol 2 (1) ◽  
pp. 68-75 ◽  
Author(s):  
L. Shahar ◽  
G. Even-Tzur
Keyword(s):  
Kinematic Model ◽  
Simultaneous Estimation ◽  
Physical Parameters ◽  
Control Network ◽  
Deformation Parameters ◽  
Free Network ◽  
Geodetic Control ◽  
Definition Of ◽  
Minimum Constraints ◽  
Entire Network

Extraction of the deterministic ingredient of a dynamic geodetic control networkA minimum constraints solution, which resolves the datum defect of a control network, is an arbitrary solution that may result in a systematic error in the estimation of the deformation parameters. This error is not derived from measurements and is usually inconsistent with the geophysical reality. A free network is affected only by errors of measurement and, therefore, a free network is an accepted way of coping with this problem. Study of deformations, which is based on the use of geodetic measurements, is usually performed today by defining a kinematic model. Such a model, when used to describe a complex geophysical environment, can lead to the partial estimation of the deterministic dynamics, which characterize the entire network. These dynamics are themselves expressed in measurements, as the adjustment systems' residuals. The current paper presents an extension of the definition of the parameters that are revalued. This extension enables the cleaning of measurements by means of the extraction of datum elements that have been defined by geodetic measurement. This cleaning minimizes the effects of these elements on the revaluated deformation. The proposed algorithm may be applied to achieve the simultaneous estimation of the physical parameters that define the geophysical activity in the network.

scholarly journals Analysis on Invulnerability of Wireless Sensor Network towards Cascading Failures Based on Coupled Map Lattice

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Xiuwen Fu ◽  
Yongsheng Yang ◽  
Haiqing Yao
Keyword(s):  
Random Network ◽  
Small World ◽  
Coupled Map Lattice ◽  
Wireless Sensor ◽  
Cascading Failures ◽  
Scale Free Network ◽  
Scale Free ◽  
Network Topologies ◽  
Free Network ◽  
Entire Network

Previous research of wireless sensor networks (WSNs) invulnerability mainly focuses on the static topology, while ignoring the cascading process of the network caused by the dynamic changes of load. Therefore, given the realistic features of WSNs, in this paper we research the invulnerability of WSNs with respect to cascading failures based on the coupled map lattice (CML). The invulnerability and the cascading process of four types of network topologies (i.e., random network, small-world network, homogenous scale-free network, and heterogeneous scale-free network) under various attack schemes (i.e., random attack, max-degree attack, and max-status attack) are investigated, respectively. The simulation results demonstrate that the rise of interference R and coupling coefficient ε will increase the risks of cascading failures. Cascading threshold values Rc and εc exist, where cascading failures will spread to the entire network when R>Rc or ε>εc. When facing a random attack or max-status attack, the network with higher heterogeneity tends to have a stronger invulnerability towards cascading failures. Conversely, when facing a max-degree attack, the network with higher uniformity tends to have a better performance. Besides that, we have also proved that the spreading speed of cascading failures is inversely proportional to the average path length of the network and the increase of average degree k can improve the network invulnerability.

Establishment of geodetic control network for Quy Nhon University area

2021 ◽  
Vol 15 (1) ◽  
pp. 61-73
Author(s):  
Quang Hien Truong ◽  
◽  
Anh Tu Ngo ◽  
Thi Hien Cu ◽  
◽  
...  
Keyword(s):  
Natural Resources ◽  
Research Result ◽  
Bench Mark ◽  
Control Network ◽  
Total Station ◽  
Network Diagram ◽  
Specialized Software ◽  
General Plan ◽  
Geodetic Control ◽  
The University

Geodetic control network of Quy Nhon University (QNU) is established based on GNSS technology and electronic total station technology in combination with the middle geometrical elevation surveying method, bench mark of network built with firm concrete installed with a centralized insulator cap. The network consists of 11 points, of which 2 points are traversed from the cadastral point of class I, used as the starting points for the traverse. The network is built based on total station method with 2 turns of forward and backward surveying. The network’s leveling height is measured by the middle geometrical elevation surveying method, ensuring compliance with the procedures and rules of the Ministry of Natural Resources and Environment. The research result includes a system of stable and solid network points, together with the coordinates and the leveling height that are closely adjusted by specialized software, control network diagram. Geodetic control network of the QNU is important in setting up map, general plan, planning, construction and serving for teaching and scientific research of the university.

Obstacle negotiation analysis of track-legged robot based on terramechanics

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Zhu Hongbiao ◽  
Yueming Liu ◽  
Weidong Wang ◽  
Zhijiang Du
Keyword(s):  
Kinematic Model ◽  
Interaction Model ◽  
Experimental Results ◽  
Physical Parameters ◽  
Negotiation Analysis ◽  
Content Type ◽  
Practical Applications ◽  
Loose Soil ◽  
Key Steps ◽  
Drawbar Pull

Purpose This paper aims to present a new method to analyze the robot’s obstacle negotiation based on the terramechanics, where the terrain physical parameters, the sinkage and the slippage of the robot are taken into account, to enhance the robot’s trafficability. Design/methodology/approach In this paper, terramechanics is used in motion planning for all-terrain obstacle negotiation. First, wheel/track-terrain interaction models are established and used to analyze traction performances in different locomotion modes of the reconfigurable robot. Next, several key steps of obstacle-climbing are reanalyzed and the sinkage, the slippage and the drawbar pull are obtained by the models in these steps. In addition, an obstacle negotiation analysis method on loose soil is proposed. Finally, experiments in different locomotion modes are conducted and the results demonstrate that the model is more suitable for practical applications than the center of gravity (CoG) kinematic model. Findings Using the traction performance experimental platform, the relationships between the drawbar pull and the slippage in different locomotion modes are obtained, and then the traction performances are obtained. The experimental results show that the relationships obtained by the models are in good agreement with the measured. The obstacle-climbing experiments are carried out to confirm the availability of the method, and the experimental results demonstrate that the model is more suitable for practical applications than the CoG kinematic model. Originality/value Comparing with the results without considering Terramechanics, obstacle-negotiation analysis based on the proposed track-terrain interaction model considering Terramechanics is much more accurate than without considering Terramechanics.

STRONGLY CORRELATED FUNCTIONS IN RELIABILITY—PHYSICAL APPROACH

1994 ◽  
Vol 01 (01) ◽  
pp. 63-69 ◽  
Author(s):  
ANDREW H. RAWICZ
Keyword(s):  
Heat Conductivity ◽  
Electrical Resistance ◽  
Physical Parameters ◽  
Strongly Correlated ◽  
Acoustic Attenuation ◽  
Chemical Parameter ◽  
New Approach ◽  
Reliability Measure ◽  
Physical Chemical ◽  
Definition Of

A new approach to reliability called Strongly Correlated Functions is proposed in this paper based on the definition of reliability as a physical magnitude rather than as a probabilistic one. The reliability measure (e.g., life-length) of a component or a product treated as a physical/chemical parameter allows for the construction of analytic correlations between the reliability measure and other physical parameters such as electrical resistance, heat conductivity, or acoustic attenuation that can be nondestructively and quickly determined by a direct measurement. Examples of Strongly Correlated Functions applied to micro wire-joints are presented.

Wind Turbine Blade Structure Parameterization Using T4T

2014 ◽  
Author(s):  
Giorgos A. Strofylas ◽  
Georgios I. Mazanakis ◽  
Ioannis K. Nikolos
Keyword(s):  
Wind Turbine ◽  
Parametric Design ◽  
Turbine Blades ◽  
Design Procedure ◽  
Software Tool ◽  
Computational Procedure ◽  
Physical Parameters ◽  
Wind Turbine Blades ◽  
Definition Of ◽  
Cloud Of Points

A software tool named “T4T” (Tools for Turbomachinery) has been developed for the parametric design of turbomachinery and wind turbine blades. The complete design procedure is object-oriented and parametric, providing the ability to the user to define various types of blades. It has been developed in QT C++, utilizing OpenCascade graphical and computational libraries. The software allows the user to design the outer surface either by specifying some physical parameters for each blade section, or by directly interpolating a surface through a cloud of points. The new/enhanced version of “T4T” software tool, introducing the definition of internal blade structure for wind turbines rotors, is fully parametric and customizable, allowing the user for defining the internal blade structure, including shear webs. The computational procedure finally produces compound solids, which can be further imported to mesh generation and analysis software through standard geometry exchange protocols, for cooperation with CFD and CSD solvers.

An Abnormal IP Traffic Detection Model Based on Scale-Free Network

2010 ◽  
Vol 44-47 ◽  
pp. 849-853
Author(s):  
Jun Li ◽  
Yan Niu
Keyword(s):  
Detection System ◽  
Anomalous Behavior ◽  
Power Exponent ◽  
Scale Free Network ◽  
Power Law Distribution ◽  
Scale Free ◽  
Detection Model ◽  
Free Network ◽  
Traffic Detection ◽  
Entire Network

A model of detecting an abnormal IP traffic in a subset of network is described. The model is based on the hypothesis that random sampling subnet are the same probability distribution as the entire network if some conditions are met with, nodes’s degree in IP traffic can be processed as a power-law distribution in scale-free network . The model analyzes the power exponent and relations between the anomalous behavior and parameter r. Finally, a test was conducted by the data, some type attacks could be identified exactly. the model provides a new framework for intrusion-detection system.

Threaded Components Under Axial Harmonic Vibration, Part 1: Experiments

1996 ◽  
Vol 118 (3) ◽  
pp. 417-422 ◽  
Author(s):  
D. P. Hess ◽  
K. Davis
Keyword(s):  
Kinematic Model ◽  
Harmonic Vibration ◽  
Static Equilibrium ◽  
Physical Parameters ◽  
Design Element ◽  
Equilibrium Conditions ◽  
Critical Design ◽  
Threaded Fasteners ◽  
Series Of Experiments ◽  
Theoretical Analyses

Threaded components have found ubiquitous use in many systems and structures. Although frequently overlooked, they represent a complex and often critical design element. One can identify numerous instances where such elements are subjected to vibratory conditions, yet their behavior in such an environment is still poorly understood. In this paper, we report on a series of experiments that were run to examine the motions of threaded fasteners subjected to axial harmonic vibration. The components are loaded by gravity and excited over a broad range of conditions. It is found that significant relative twisting motion can occur both with and against the load. This indicates that threaded components may loosen or tighten in the presence of vibration. It is shown that the direction of twist depends on the frequency and amplitude of the vibratory input as well as various physical parameters. Previous theoretical analyses of threaded components under vibration are based on static equilibrium conditions, and only predict a loosening action, i.e., twist with load. In Part 2 of this paper, a kinematic model is developed which predicts twisting both with and against load as observed in the experiments.

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