Analysis and Evaluation of Various Tropospheric Modeling Approaches for High-Precision GPS Kinematic Positioning over Medium Ranges and at High Altitude: Case Study

2009 ◽  
Vol 135 (2) ◽  
pp. 66-71 ◽  
Author(s):  
S.-H. Zhao ◽  
X.-S. Lu ◽  
Q.-F. Wang ◽  
G.-R. Hu ◽  
C. Ogaja
Keyword(s):  
High Altitude ◽  
High Precision ◽  
Analysis And Evaluation ◽  
Kinematic Positioning ◽  
Modeling Approaches

scholarly journals Operations Scheduling of Sugarcane Production Using Classical GERT Method (Part I: Land Preparation, Planting and Preserve Operations)

2015 ◽  
Vol 3 (2) ◽  
pp. 71
Author(s):  
Nasim Monjezi ◽  
Mohammad Javad Sheikhdavoodi ◽  
Hasan Zakidizaji ◽  
Afshin Marzban ◽  
Mahmood Shomeili
Keyword(s):  
Environmental Conservation ◽  
Agricultural Systems ◽  
Sugarcane Production ◽  
Khuzestan Province ◽  
Land Preparation ◽  
Analysis And Evaluation ◽  
Project Completion ◽  
Operations Scheduling ◽  
Gert Networks

Analysis and evaluation of agricultural systems use these criteria: energy, economic, agronomy, environmental conservation and time. Because of time importance indicator for reducing timeliness cost, project scheduling techniques are used. Graphical Evaluation and Review Technique (GERT) is widely used as a tool for managing projects. In this research GERT Networks were used and operations scheduling of sugarcane production (land preparation, planting and preserve operations) in Khuzestan province of Iran as a case study was analysed, by using WinQsb software. Critical activities, events and path were determined. The earliest project completion time is 214.03 days. The results show a high potential for operations scheduling of sugarcane production.

scholarly journals Case Study: Comparative Analysis of Hydrologic Simulations with Areal-Averaging of Moving Rainfall

Hydrology ◽  
2019 ◽  
Vol 6 (1) ◽  
pp. 12 ◽  
Author(s):  
Zheng N. Fang ◽  
Michael J. Shultz ◽  
Kevin J. Wienhold ◽  
Jiaqi Zhang ◽  
Shang Gao
Keyword(s):  
Comparative Analysis ◽  
Peak Discharge ◽  
Distributed Model ◽  
Lumped Model ◽  
Modeling Approaches ◽  
Flood Peaks ◽  
The Difference ◽  
Hydrologic Responses ◽  
The Impact

The goal of this investigation is to compare the hydrologic simulations caused by the areal-averaging of dynamic moving rainfall. Two types of synthetic rainfall are developed: spatially varied rainfall (SVR) is the typical input to a distributed model while temporally varied rainfall (TVR) emulates SVR but is spread uniformly over the entire watershed as in the case of a lumped model. This study demonstrates a direct comparison of peak discharge and peak timing generated by synthetic moving storms over idealized rectangular basins and a real watershed. It is found that the difference between the hydrologic responses from SVR and TVR reflects the impact from the areal-averaging of rainfall; the areal-averaging of rainfall for the movement from upstream to downstream over a lumped model can result in underestimated and delayed peak values in comparison to those from a distributed model; the flood peaks from SVR and TVR are found similar when the storm moves from downstream to upstream. The findings of the study suggest that extra cautions are needed for practitioners when evaluating simulated results from distributed and lumped modeling approaches even using the same rainfall information.

A Compliance-Based Compensation Approach for Designing High-Precision Flexure Mechanism

2012 ◽  
Author(s):  
S. Z. Li ◽  
J. J. Yu ◽  
G. H. Zong ◽  
Hai-jun Su
Keyword(s):  
High Precision ◽  
Motion Compensation ◽  
Design Method ◽  
Flexure Mechanism ◽  
Parasitic Motion ◽  
Translation Error ◽  
Fea Simulation ◽  
Compensation Approach ◽  
Robust Design Method

This paper presents an approach of utilizing parasitic motion compensation for designing high-precision flexure mechanism. This approach is expected to improve the accuracy of flexure mechanism without changing its degree of freedom (DOF) characteristic. Different from the method which mainly concentrates on how to compensate the parasitic translation error of a parallelogram-type flexure mechanism existing in most of the literatures, the proposed approach can compensate the parasitic motion produced by rotation in company with translation. Besides, the parasitic motion of a flexure mechanism is formulated and evaluated by utilizing its compliance. To specify it, the compliance of a general flexure mechanism is calculated firstly. Then the parasitic motions introduced by both rotation and translation are analyzed by utilizing the resultant compliance. Subsequently, a compliance-based compensation approach is addressed as the most important part of this paper. The design principles and procedure are further proposed in detail to help with improving the accuracy of the flexure mechanism. Finally, a case study of a 2R1T flexure mechanism is provided to illustrate this approach, and FEA simulation is implemented to demonstrate its validity. The result shows that it is a robust design method for the design of high-precision flexure mechanism.

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