A System-Dynamics-Based Hazard Analysis of Inverted-Pendulum Human Transporters

2013 ◽  
Author(s):  
Christopher Adams ◽  
William Singhose ◽  
Dooroo Kim
Keyword(s):  
System Dynamics ◽  
Systematic Approach ◽  
Inverted Pendulum ◽  
Mechanical Design ◽  
Hazard Analysis ◽  
Detailed Knowledge ◽  
Operating Environment ◽  
Complex Dynamic ◽  
Wide Range

Best practices in product design require engineers to perform preliminary hazard analyses on the most promising conceptual designs, as well as a more rigorous hazard analysis when the details of the product are being finalized. When the product is a complex dynamic system that interacts directly with a human, the engineers must consider the wide range of possible motions and forces that the device could create. Such an analysis goes beyond a simple thought exercise and requires detailed knowledge about the system dynamics and operating environment. This paper presents such an analysis of an inverted-pendulum human transporter. The list of hazards is constructed by using fundamental knowledge of the dynamics and the mechanical design obtained through simulation and experimentation. However, the dynamics are so complex that the list is augmented with hazards that are revealed by searching through accident videos posted on the Internet. The severity of each hazard is estimated using an energy-based measurement of the hazard onset conditions. While this case study is interesting, it also provides a systematic approach to hazard analysis that can be applied to other complex and dangerous dynamic systems.

A Dynamics-Based Hazard Analysis of Inverted-Pendulum Human Transporters Using Data-Mined Information

2016 ◽  
Vol 2 (3) ◽  
Author(s):  
William Singhose ◽  
Christopher Adams ◽  
Dooroo Kim
Keyword(s):  
Inverted Pendulum ◽  
Mechanical Design ◽  
Hazard Analysis ◽  
The Internet ◽  
Detailed Knowledge ◽  
Operating Environment ◽  
Complex Dynamic ◽  
Wide Range ◽  
Simulation Results ◽  
Using Data

When a product is a complex dynamic system that interacts directly with a human, engineers must consider a wide range of possible motions and forces that the device could exert on the human. Such an analysis goes beyond a simple thought exercise and requires detailed knowledge about the system dynamics and the operating environment. This paper presents such an analysis of inverted-pendulum human transporters. The list of hazards is constructed by using knowledge of the dynamics and mechanical design obtained through simulation and experimentation. However, the dynamics are so complex that the list is augmented with hazards that are revealed by studying accident videos posted on the Internet. The severity of the hazards is estimated using an energy-based measurement of the hazard onset conditions as well as compounding factors from the mechanical design. In addition, experimental and simulation results of sample hazard conditions illustrate their danger and severity. The analysis reveals that inverted-pendulum human transporters have several hazards with unacceptable risk.

Dynamic Effects of Obstacles on Two-Wheeled Inverted-Pendulum Transporters

2015 ◽  
Author(s):  
John Harber ◽  
Christopher Adams ◽  
Arnoldo Castro ◽  
William Singhose
Keyword(s):  
Experimental Investigation ◽  
Control System ◽  
Inverted Pendulum ◽  
Mechanical Design ◽  
Vertical Direction ◽  
Dynamic Effects ◽  
Operating Environment ◽  
Wheeled Inverted Pendulum ◽  
Approach Speed ◽  
Small Footprint

Two-wheeled inverted pendulums can be used as personal transporters. Their maneuverability and small footprint give them some desirable properties for this application. However, given the unstable mechanical design and the complicated control system that is required, inverted pendulums make complex and unexpected motions in response to both movements of the rider and disturbances from the operating environment. These complex motions lead to dynamic hazards that may cause the rider to fall off or the device to fall over. To better understand some of the complex motions, the response of a two-wheeled inverted-pendulum transporter traveling over bumps of various sizes is studied. Three effects of riding over bumps are demonstrated through an experimental investigation. When striking a bump, the transporter may bounce in the vertical direction, depending on the approach speed and size of the bump. Bumps also cause the transporter to pitch forward. When striking a bump with one wheel, the transporter turns towards the bump. All three effects can act to destabilize the machine and rider.

Site specific agricultural soil management with the use of new technologies

2013 ◽  
Vol 16 (1) ◽  
pp. 59-67
Keyword(s):  
New Technologies ◽  
Digital Interface ◽  
Appropriate Treatment ◽  
Wide Range ◽  
Soil Variation ◽  
Soil Information ◽  
Remote Sensing Techniques ◽  
Agricultural Areas

<p>The Soil Science Institute of Thessaloniki produces new digitized Soil Maps that provide a useful electronic database for the spatial representation of the soil variation within a region, based on in situ soil sampling, laboratory analyses, GIS techniques and plant nutrition mathematical models, coupled with the local land cadastre. The novelty of these studies is that local agronomists have immediate access to a wide range of soil information by clicking on a field parcel shown in this digital interface and, therefore, can suggest an appropriate treatment (e.g. liming, manure incorporation, desalination, application of proper type and quantity of fertilizer) depending on the field conditions and cultivated crops. A specific case study is presented in the current work with regards to the construction of the digitized Soil Map of the regional unit of Kastoria. The potential of this map can easily be realized by the fact that the mapping of the physicochemical properties of the soils in this region provided delineation zones for differential fertilization management. An experiment was also conducted using remote sensing techniques for the enhancement of the fertilization advisory software database, which is a component of the digitized map, and the optimization of nitrogen management in agricultural areas.</p>

Oxford Studies in Ancient Philosophy, Volume 55

2018 ◽  
Keyword(s):  
Middle Ages ◽  
Ancient Philosophy ◽  
Recent Book ◽  
Loss Of Control ◽  
Ancient Greek ◽  
Original Essays ◽  
Constant Change ◽  
Wide Range ◽  
Metaphysical Principle

Oxford Studies in Ancient Philosophy provides, twice each year, a collection of the best current work in the field of ancient philosophy. Each volume features original essays that contribute to an understanding of a wide range of themes and problems in all periods of ancient Greek and Roman philosophy, from the beginnings to the threshold of the Middle Ages. From its first volume in 1983, OSAP has been a highly influential venue for work in the field, and has often featured essays of substantial length as well as critical essays on books of distinctive importance. Volume LV contains: a methodological examination on how the evidence for Presocratic thought is shaped through its reception by later thinkers, using discussions of a world soul as a case study; an article on Plato’s conception of flux and the way in which sensible particulars maintain a kind of continuity while undergoing constant change; a discussion of J. L. Austin’s unpublished lecture notes on Aristotle’s Nicomachean Ethics and his treatment of loss of control (akrasia); an article on the Stoics’ theory of time and in particular Chrysippus’ conception of the present and of events; and two articles on Plotinus, one that identifies a distinct argument to show that there is a single, ultimate metaphysical principle; and a review essay discussing E. K. Emilsson’s recent book, Plotinus.

scholarly journals System Dynamics-Multiple Objective Optimization Model for Water Resource Management: A Case Study in Jiaxing City, China

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 671
Author(s):  
Xiaoying Zhou ◽  
Feier Wang ◽  
Kuan Huang ◽  
Huichun Zhang ◽  
Jie Yu ◽  
...  
Keyword(s):  
Resource Management ◽  
System Dynamics ◽  
Water Resource ◽  
Water Allocation ◽  
Water Resource Management ◽  
Water Shortage ◽  
Multiple Objective ◽  
Multiple Objective Optimization ◽  
Model Framework

Predicting and allocating water resources have become important tasks in water resource management. System dynamics and optimal planning models are widely applied to solve individual problems, but are seldom combined in studies. In this work, we developed a framework involving a system dynamics-multiple objective optimization (SD-MOO) model, which integrated the functions of simulation, policy control, and water allocation, and applied it to a case study of water management in Jiaxing, China to demonstrate the modeling. The predicted results of the case study showed that water shortage would not occur at a high-inflow level during 2018–2035 but would appear at mid- and low-inflow levels in 2025 and 2022, respectively. After we made dynamic adjustments to water use efficiency, economic growth, population growth, and water resource utilization, the predicted water shortage rates decreased by approximately 69–70% at the mid- and low-inflow levels in 2025 and 2035 compared to the scenarios without any adjustment strategies. Water allocation schemes obtained from the “prediction + dynamic regulation + optimization” framework were competitive in terms of social, economic and environmental benefits and flexibly satisfied the water demands. The case study demonstrated that the SD-MOO model framework could be an effective tool in achieving sustainable water resource management.

scholarly journals Differences in echocardiography interpretation techniques among trainees and expert readers

2021 ◽  
Author(s):  
David Roy Anderson ◽  
Sarah Blissett ◽  
Patricia O’Sullivan ◽  
Atif Qasim
Keyword(s):  
Diagnostic Accuracy ◽  
Systematic Approach ◽  
Qualitative Case Study ◽  
First Year ◽  
Educational Tool ◽  
Thought Processes ◽  
Advanced Imaging ◽  
Multiple Images ◽  
Novice Readers

Abstract Background Trainees learn transthoracic echocardiogram (TTE) interpretation through independently completing and reviewing selected portions of the study with experts. The diagnostic accuracy of novice TTE interpretation is known to be low and schema for reading TTEs systematically are lacking. The purpose of our study is to identify techniques experts use while reading TTEs which could be used to more effectively teach novice readers. Methods We performed a prospective qualitative case study to observe how experts and trainees interpret TTEs in an academic institution using a concurrent think aloud (CTA) method. Three TTEs of intermediate complexity were given to 3 advanced imaging fellows, 3 first year fellows and 3 expert TTE readers Participants filled out a report while reading and described aloud their thought processes. Sessions were video and audiotaped for analysis. Results Experts and advanced fellows used specific techniques that novices did not including: previewing studies, reviewing multiple images simultaneously, having flexibility in image review order and disease coding, and saving hardest elements to code for the end. Direct observation of TTE reading informed trainee inefficiencies and was a well-received educational tool. Conclusions In this single centered study we identified several unique approaches experts use to interpret TTEs which may be teachable to novices. Although limited in generalizability the findings of this study suggests that a more systematic approach to TTE interpretation, using techniques found in experts, might be of significant value for trainees. Further study is needed to evaluate teaching practices at other institutions and to assess whether implementation of these techniques by novices improves can improve their diagnostic accuracy and efficiency of reading at an earlier stage in their training.

Urban flood hazard analysis in present and future climate after statistical downscaling: a case study in Ha Tinh city, Vietnam

2021 ◽  
Vol 18 (4) ◽  
pp. 257-274
Author(s):  
T. T. A. Le ◽  
N. T. Lan-Anh ◽  
V. Daskali ◽  
B. Verbist ◽  
K. C. Vu ◽  
...  
Keyword(s):  
Statistical Downscaling ◽  
Flood Hazard ◽  
Hazard Analysis ◽  
Future Climate ◽  
Urban Flood

scholarly journals Assessing the Relation between Mud Components and Rheology for Loss Circulation Prevention Using Polymeric Gels: A Machine Learning Approach

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1377
Author(s):  
Musaab I. Magzoub ◽  
Raj Kiran ◽  
Saeed Salehi ◽  
Ibnelwaleed A. Hussein ◽  
Mustafa S. Nasser
Keyword(s):  
Machine Learning ◽  
Rheological Properties ◽  
Nearest Neighbor ◽  
Drilling Fluid ◽  
Gradient Boosting ◽  
K Nearest Neighbor ◽  
Wide Range ◽  
Machine Learning Approach ◽  
Drilling Operations

The traditional way to mitigate loss circulation in drilling operations is to use preventative and curative materials. However, it is difficult to quantify the amount of materials from every possible combination to produce customized rheological properties. In this study, machine learning (ML) is used to develop a framework to identify material composition for loss circulation applications based on the desired rheological characteristics. The relation between the rheological properties and the mud components for polyacrylamide/polyethyleneimine (PAM/PEI)-based mud is assessed experimentally. Four different ML algorithms were implemented to model the rheological data for various mud components at different concentrations and testing conditions. These four algorithms include (a) k-Nearest Neighbor, (b) Random Forest, (c) Gradient Boosting, and (d) AdaBoosting. The Gradient Boosting model showed the highest accuracy (91 and 74% for plastic and apparent viscosity, respectively), which can be further used for hydraulic calculations. Overall, the experimental study presented in this paper, together with the proposed ML-based framework, adds valuable information to the design of PAM/PEI-based mud. The ML models allowed a wide range of rheology assessments for various drilling fluid formulations with a mean accuracy of up to 91%. The case study has shown that with the appropriate combination of materials, reasonable rheological properties could be achieved to prevent loss circulation by managing the equivalent circulating density (ECD).

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