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Optimal Trajectory Planning of a Mobile Robot with Spatial Manipulator For Obstacle Avoidance
Shariati Nia Mostafa,Ghayour Mostafa,Mosayebi Masoud 제어로봇시스템학회 2010 제어로봇시스템학회 국제학술대회 논문집 Vol.2010 No.10
Mobile robots consist of a mobile platform with one or many manipulators mounted on it are of great interest in a number of applications. Combination of platform and manipulator causes robot operates in extended work space. The analysis of these systems includes kinematics redundancy that makes more complicated problem. However, it gives more feasibility to robotic systems because of the existence of multiple solutions in a specified workspace. This paper presents a methodology in generating paths and trajectories for both the mobile platform and a 3DOF manipulator mounted on it, in the presence of obstacles. Obstacles add kinematics constraint into optimization problem. The method employs smooth and continuous functions such as polynomials. The proposed method includes obtaining time history of the mobile robot motion. It is supposed that the obstacles can be enclosed in cylinders. The platform has been used in this research is a differentially-driven platform. The core of the method is based on mapping the nonholonomic constraint to a space where it can be satisfied trivially. A suitable criterion can be used to solve an optimization problem to find the optimal solution. In this research, the problem of path planning with simultaneous optimization of kinematics and dynamic indices has been accomplished using genetic algorithm in order to find the global optimum solution. The validity of the methodology is demonstrated by using a differential-drive mobile manipulator system, various simulations of platform with a spatial 3-link manipulator are presented to show the effectiveness of the presented method.
Output-only structural damage detection under multiple unknown white noise excitations
Pinghe Nia,Xiaojuan Wang,Hongyuan Zhou 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.79 No.3
Most of the existing output-only damage detection methods require the number of sensors should be larger than the number of unknown excitation force, and the force location should be available. This paper presents a novel output-only damage detection method without these requirements. The proposed method is based on the correlation function of acceleration responses. When the structure is under white noise excitations (or ambient excitations), the correlation function of acceleration responses can be treated as free vibration responses with unknown initial conditions. The unknown structural parameters and initial conditions can be simultaneously identified by minimizing the difference between the measured and calculated correlation functions. The unknown initial conditions are identified with state space method and the unknown structural parameters are updated with sensitivity method. Numerical studies of a 2D truss and a five-bay 3D frame structure are conducted to demonstrate the accuracy, effectiveness, and robustness of the proposed method. Experimental studies on an eight-floor steel frame are further carried out. Results show that the proposed method is not only insensitive to environmental noise but also applicable when the number of sensors is less than that of unknown excitations. Also, the proposed method can be used for damage detection when the force location is unknown.
Dynamic mix design optimization of high-performance concrete
Ali Ziaei-Nia,Mahdi Shariati,Elnaz Salehabadi 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.29 No.1
High performance concrete (HPC) depends on various parameters such as the type of cement, aggregate and water reducer amount. Generally, the ready concrete company in various regions according to the requirements and costs, mix design of concrete as well as type of cement, aggregates, and, amount of other components will vary as a result of moment decisions or dynamic optimization, though the ideal conditions will be more applicable for the design of mix proportion of concrete. This study aimed to apply dynamic optimization for mix design of HPC; consequently, the objective function, decision variables, input and output variables and constraints are defined and also the proposed dynamic optimization model is validated by experimental results. Results indicate that dynamic optimization objective function can be defined in such a way that the compressive strength or performance of all constraints is simultaneously examined, so changing any of the variables at each step of the process input and output data changes the dynamic of the process which makes concrete mix design formidable.
A Coordinated Heuristic Approach for Virtual Network Embedding in Cloud Infrastructure
( Nahid Hamzehee Nia ),( Sepideh Adabi ),( Majid Nikougoftar Nategh ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.5
A major challenge in cloud infrastructure is the efficient allocation of virtual network elements on top of substrate network elements. Path algebra is a mathematical framework which allows the validation and convergence analysis of the mono-constraint or multi-constraint routing problems independently of the network topology or size. The present study proposes a new heuristic approach based on mathematical framework "paths algebra" to map virtual nodes and links to substrate nodes and paths in cloud. In this approach, we define a measure criterion to rank the substrate nodes, and map the virtual nodes to substrate nodes according to their ranks by using a greedy algorithm. In addition, considering multi-constraint routing in virtual link mapping stage, the used paths algebra framework allows a more flexible and extendable embedding. Obtained results of simulations show appropriate improvement in acceptance ratio of virtual networks and cost incurred by the infrastructure networks.
BIFURCATIONS OF STOCHASTIC IZHIKEVICH-FITZHUGH MODEL
Mehdi Fatehi Nia,Elaheh Mirzavand 호남수학회 2022 호남수학학술지 Vol.44 No.3
Noise is a fundamental factor to increased validity and regularity of spike propagation and neuronal firing in the nervous system. In this paper, we examine the stochastic version of the Izhikevich-FitzHugh neuron dynamical model. This approach is based on techniques presented by Luo and Guo, which provide a general framework for the bifurcation and stability analysis of two dimensional stochastic dynamical system as an Itˆo averaging diffusion system. By using largest lyapunov exponent, local and global stability of the stochastic system at the equilibrium point are investigated. We focus on the two kinds of stochastic bifurcations: the P-bifurcation and the D-bifurcations. By use of polar coordinate, Taylor expansion and stochastic averaging method, it is shown that there exists choices of diffusion and drift parameters such that these bifurcations occurs. Finally, numerical simulations in various viewpoints, including phase portrait, evolution in time and probability density, are presented to show the effects of the diffusion and drift coefficients that illustrate our theoretical results.
Functional Quails Eggs using Enriched Spirulina during the Biosorption Process
Maryam Vejdani nia,Mozhgan Emtyazjoo,Mohammad Chamani 한국축산식품학회 2022 한국축산식품학회지 Vol.42 No.1
Spirulina platensis was included at 2.5%, 5%, and 7.5% of the diet as a phytobiotic either as a crude preparation or after enrichment by a biosorption process and fed to 126 Japanese quail and the eggs collected and examined for 6 weeks. Assessments were made of physical and chemical characteristics of the eggs. All treatments with added Spirulina increased unsaturated fatty acids and decreased saturated fatty acids with the largest responses for linolenic (omega 3) and oleic (omega 9) acids. The changes in fatty acids were greater with enriched than crude Spirulina. These results suggest that eggs from quail fed with Spirulina may have positive effects on human health.