Search results for "75"

Simulation Goals and Metrics Identification

2016

Agent-Based Modeling and Simulation (ABMS) is a very useful means for producing high quality models during simulation studies. When ABMS is part of a methodological ap- proach it becomes important to have a method for identifying the objectives of the simulation study in a disciplined fashion. In this work we propose a set of guidelines for properly capturing and representing the goals of the simulations and the metrics, allowing and evaluating the achievement of a simulation objective. We take inspiration from the goal-question-metric approach and with the aid of a specific problem formalization we are able to derive the right questions for relating simulation goals and metrics.

Feasibility study of electromechanical cylinder drivetrain for offshore mechatronic systems

2017

Currently, there is an increasing focus on the environmental impact and energy consumption of the oil and gas industry. In offshore drilling equipment, electric motors tend to replace traditionally used hydraulic motors, especially in rotational motion control applications. However, force densities available from linear hydraulic actuators are still typically higher than those of electric actuators. Therefore, usually the remaining source of hydraulic power is thereby the hydraulic cylinder. This paper presents a feasibility study on the implementation of an electromechanical cylinder drivetrain on an offshore vertical pipe handling machine. The scope of this paper is to investigate the fea…

Enhancement of mechanical properties of FSWed AA7075 lap joints through in-situ fabrication of MMC

2017

Abstract Friction Stir Processing (FSP) has been demonstrated feasible to create local Metal Matrix Composites (MMCs) in light alloys matrix. In this research, local MMCs were produced contextually to the weld using Friction Stir Welding (FSW). SiC particles were added to AA7075 lap joints by creating a proper groove on the top surface of the bottom sheet. Different welds were produced with increasing number of tool passes. The effect of the multiple passes was investigated through shear tests, macro and micro observations, average grain size and microhardness measurements. The welded joints were compared to a reference weld produced with no reinforcements. It was found that poor mixing bet…

Adaptive Fuzzy Super-Twisting Sliding Mode Control for Microgyroscope

2019

This paper proposes a novel adaptive fuzzy super-twisting sliding mode control scheme for microgyroscopes with unknown model uncertainties and external disturbances. Firstly, an adaptive algorithm is used to estimate the unknown parameters and angular velocity of microgyroscopes. Secondly, in order to improve the performance of the system and the superiority of the super-twisting algorithm, this paper utilizes the universal approximation characteristic of the fuzzy system to approach the gain of the super-twisting sliding mode controller and identify the gain of the controller online, realizing the adaptive adjustment of the controller parameters. Simulation results verify the superiority a…

Design and Calibration of a Specialized Polydioptric Camera Rig

2017

International audience; It has been observed in the nature that all creatures have evolved highly exclusive sensory organs depending on their habitat and the form of resources availability for their survival. In this project, a novel omnidirectional camera rig, inspired from natural vision sensors, is proposed. It is exclusively designed to operate for highly specified tasks in the field of mobile robotics. Navigation problems on uneven terrains and detection of the moving objects while the robot is itself in motion are the core problems that omnidirectional systems tackle. The proposed omnidirectional system is a compact and a rigid vision system with dioptric cameras that provide a 360° f…

A model for torque losses in variable displacement axial piston motors

2018

This paper includes a comparison of earlier presented models for torque losses in hydraulic motors and several proposed models that all rely on data typically available for a system engineer. The new models and the old ones are compared. The new models are all based on a model developed by Jeong 2007 with an expansion that include variable displacement. All of the new models yield very good accuracy down to approximately 50% of maximum displacement and down to approximately 15% of maximum speed. In these operational ranges the deviation in torque is less than 1%. The main purpose of the new models is to facilitate simulations of hydraulically actuated winches with a balance between accuracy…

Fusta de les serres ibériques (1750-1790) : L'impacte de la demanda per a la construcció fluvial a Cartagena

2014

Aportación hispánica a la historia de la guitarra española hasta la publicación de las reglas de Pablo Minguet en 1754

2019

“As Many as Possible for as Long as Possible”—A Case Study of a Soccer Team That Fosters Multiple Outcomes

2021

The personal assets framework suggests that dynamic elements of (a) personal engagement in activities, (b) quality social dynamics, and (c) appropriate settings will influence an athlete’s long-term outcomes of performance, personal development, and continued participation in sport. The aim of the present study was to conduct a case study of a Norwegian age-restricted team that was successful in promoting participation, performance, and positive development for individual participants and to investigate how the dynamic elements of activities, social dynamics, and settings have led to these long-term outcomes. The results indicated that the case is a best-practice example of successful attai…

Extracellular Vesicles Shed by Melanoma Cells Contain a Modified Form of H1.0 Linker Histone and H1.0 mRNA-binding Proteins

2016

Extracellular vesicles (EVs) are shed in the extracellular environment by both prokaryotes and eukaryotes. Although produced from both normal and cancer cells, malignant cells release a much higher amount of EVs, which also contain tumor-specific proteins and RNAs. We previously found that G26/24 oligodendroglioma cells shed EVs that contain the pro-apoptotic factors FasL and TRAIL1-2. Interestingly, G26/24 release, via EVs, extracellular matrix remodelling proteases3, and H1° histone protein4, and mRNA. To shed further light on the role of EVs in discarding proteins and mRNAs otherwise able to counteract proliferative signals, we studied a melanoma cell line (A375). We found that also thes…