A Case Study of a Modified Gravity Type Cage and Mooring System Using Numerical and Physical Models

2005 ◽  
Vol 30 (1) ◽  
pp. 47-58 ◽  
Author(s):  
J. DeCew ◽  
D.W. Fredriksson ◽  
L. Bugrov ◽  
M.R. Swift ◽  
O. Eroshkin ◽  
...  
Keyword(s):  
Modified Gravity ◽  
Physical Models ◽  
Mooring System

Formalizing the Mapping of UML Conceptual Schemas to Column-Oriented Databases

2018 ◽  
Vol 14 (3) ◽  
pp. 44-68 ◽  
Author(s):  
Fatma Abdelhedi ◽  
Amal Ait Brahim ◽  
Gilles Zurfluh
Keyword(s):  
Big Data ◽  
Data Warehouse ◽  
Relational Databases ◽  
Traditional Approach ◽  
Physical Models ◽  
Decision Making Process ◽  
Nosql Databases ◽  
Care Field ◽  
Sufficient Degree

Nowadays, most organizations need to improve their decision-making process using Big Data. To achieve this, they have to store Big Data, perform an analysis, and transform the results into useful and valuable information. To perform this, it's necessary to deal with new challenges in designing and creating data warehouse. Traditionally, creating a data warehouse followed well-governed process based on relational databases. The influence of Big Data challenged this traditional approach primarily due to the changing nature of data. As a result, using NoSQL databases has become a necessity to handle Big Data challenges. In this article, the authors show how to create a data warehouse on NoSQL systems. They propose the Object2NoSQL process that generates column-oriented physical models starting from a UML conceptual model. To ensure efficient automatic transformation, they propose a logical model that exhibits a sufficient degree of independence so as to enable its mapping to one or more column-oriented platforms. The authors provide experiments of their approach using a case study in the health care field.

A risk management approach to safe mooring systems in Australia

2016 ◽  
Vol 56 (2) ◽  
pp. 550
Author(s):  
Paul Sullivan
Keyword(s):  
Working Group ◽  
Steering Committee ◽  
Management Approach ◽  
Regulatory Regime ◽  
System Management ◽  
Mooring System ◽  
Offshore Drilling ◽  
Tropical Waters ◽  
Drilling Unit

In March 2015, during cyclone Olwyn, a mobile offshore drilling unit (MODU) experienced a mooring failure and loss of position event. The MODU was blown some three nautical miles off location in the vicinity of subsea and surface infrastructure. There are serious safety, environmental, financial, and reputational risks that can be presented by a loss of mooring position. In response, NOPSEMA hosted a workshop with members of APPEA, the International Drilling Contractors Association (IADC) and with mooring contractors with a view to collectively improve the management of risks associated with the mooring of MODUs in Australia’s tropical waters, both in the short and longer term. Following this workshop, NOPSEMA issued an Information Note for the 2015/16 cyclone season, describing the regulators’ expectations of industry duty holders in respect of MODU mooring system management. At the same time, APPEA’s Drilling Industry Steering Committee (DISC) members aligned on the key principles underpinning a MODU mooring system approach. In late 2015, the APPEA DISC members commissioned a working group to develop a guidance framework for MODU mooring management in Australian tropical waters. DISC aims to work closely with industry partners such as IADC and specialist mooring contractors in the development of this framework. DISC has tasked the working group to have the guidance framework ready for the 2016/17 cyclone season, and for presentation at the 2016 APPEA Conference. The completed case study, presented at the APPEA Conference, provides an excellent example of a goal-setting and continuous improvement regulatory regime working as designed and intended.

scholarly journals Silo with a Corrugated Sheet Wall

2013 ◽  
Vol 21 (3) ◽  
pp. 19-30 ◽  
Author(s):  
Csaba Németh ◽  
Ján Brodniansky
Keyword(s):  
Computational Models ◽  
Bending Moment ◽  
Physical Models ◽  
Experimental Measurements ◽  
Bending Moments ◽  
Bulk Materials ◽  
Production And Consumption ◽  
Thin Walled ◽  
The Mathematical Model

Abstract Silos and tanks are currently being used to create reserves of stored materials. Their importance is based on balancing the production and consumption of bulk materials to establish an adequate reserve throughout the year. The case study introduced within the framework of this paper focuses on thin-walled silos made of corrugated sheets and on an approach for designing these types of structures. The storage of bulk materials causes compression or tensile stresses in the walls of a silo structure. The effect of a frictional force in the silo walls creates an additional bending moment in a wave, which ultimately affects the resulting bending moments. Several mathematical and physical models were used in order to examine various types of loading and their effects on a structure. Subsequently, the accuracy of the computational models was verified by experimental measurements on a grain silo in Bojničky, Slovakia. A comparison of the experimental and mathematical models shows a reasonable match and confirms the load specifications, while indicating that the mathematical model was correct.

A Modified Gravity p-Median Model for Optimizing Facility Locations

2018 ◽  
Vol 6 (5) ◽  
pp. 421-434 ◽  
Author(s):  
Zhuolin Tao ◽  
Qingjing Zheng ◽  
Hui Kong
Keyword(s):  
Modified Gravity ◽  
Distance Decay ◽  
Decay Parameter ◽  
Distance Threshold ◽  
Facility Locations ◽  
Spatial Equity ◽  
Average Travel Time ◽  
Tertiary Hospitals ◽  
The Difference

AbstractThe gravityp-median model is an important improvement to the widely-usedp-median model. However, there is still a debate on its validity in empirical applications. Previous studies even doubt the significance of the gravityp-median model. Using a case study of tertiary hospitals in Shenzhen, China, this study re-examines the difference between the gravityp-median model with thep-median model, by decomposing the difference between the two models into gravity rule and variant attraction. This study also proposes a modified gravityp-median model by incorporating a distance threshold. The empirical results support the validity of the gravityp-median model, and also reveal that only when the attractions of candidate facility locations are variable will the gravityp-median model lead to different results with thep-median model. The difference between the modified gravityp-median model and the gravityp-median model is also examined. Moreover, the impacts of the distance-decay parameter and distance threshold on solutions are investigated. Results indicate that a larger distance-decay parameter tends to result in a more dispersed distribution of optimal facilities and a smaller average travel time, and a smaller distance threshold can better promote the spatial equity of facilities. The proposed method can also be applied in studies of other types of facilities or in other areas.

scholarly journals Spanning the complexity chasm: A research approach to move from simple to complex engineering systems

2014 ◽  
Vol 28 (4) ◽  
pp. 369-384 ◽  
Author(s):  
Vimal Viswanathan ◽  
Julie Linsey
Keyword(s):  
Design Thinking ◽  
Physical Models ◽  
Research Approach ◽  
Engineering System ◽  
Engineering Systems ◽  
Complex Engineering ◽  
Complex Engineering Systems ◽  
Complex System Design ◽  
Cost Effect

AbstractA multistudy approach is presented that allows design thinking of complex systems to be studied by triangulating causal controlled lab findings with coded data from more complex products. A case study illustration of this approach is provided. During the conceptual design of engineering systems, designers face many cognitive challenges, including design fixation, errors in their mental models, and the sunk cost effect. These factors need to be mitigated for the generation of effective ideas. Understanding the effects of these challenges in a realistic and complex engineering system is especially difficult due to a variety of factors influencing the results. Studying the design of such systems in a controlled environment is extremely challenging because of the scale and complexity of such systems and the time needed to design the systems. Considering these challenges, a mixed-method approach is presented for studying the design thinking of complex engineering systems. This approach includes a controlled experiment with a simple system and a qualitative cognitive-artifacts study on more complex engineering systems followed by the triangulation of results. The triangulated results provide more generalizable information for complex system design thinking. This method combines the advantages of quantitative and qualitative study methods, making them more powerful while studying complex engineering systems. The proposed method is illustrated further using an illustrative study on the cognitive effects of physical models during the design of engineering systems.

scholarly journals Emulators of a Physical Model for Estimating Leaf Wetness Duration

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 216
Author(s):  
Ju-Young Shin ◽  
Junsang Park ◽  
Kyu Rang Kim
Keyword(s):  
Wind Speed ◽  
Physical Model ◽  
Learning Algorithm ◽  
Physical Models ◽  
Leaf Wetness ◽  
Estimation Model ◽  
Leaf Wetness Duration ◽  
Speed Measurement ◽  
Wind Speed Measurement

Leaf wetness duration (LWD) has rarely been measured due to lack of standard protocol. Thus, empirical and physical models have been proposed to resolve this gap. Although the physical model provides robust performance in diverse conditions, it requires many variables. The empirical model requires fewer variables; nevertheless, its performance is specific to a given condition. A universal LWD estimation model using fewer variables is thus needed to improve LWD estimation. The objective of this study was to develop emulators of the LWD estimation physical model for use as universal empirical models. It is assumed that the Penman–Monteith (PM) model determines LWD and can be employed as a physical model. In this study, a simulation was designed and conducted to investigate the characteristics of the PM model and to build the emulators. The performances of the built emulators were evaluated based on a case study of LWD data obtained in South Korea. It was determined that a machine learning algorithm can properly emulate the PM model in LWD estimations based on the simulation. Moreover, the poor performances of some emulators that use wind speed may have been due to the limitation of wind speed measurement. The accuracy of the anemometer is thus critical to estimating LWD using physical models. A deep neural network using relative humidity and air temperature was found to be the most appropriate emulator of those tested for LWD estimation.

scholarly journals Design Optimisation for 3D printed SLM objects

2021 ◽  
Author(s):  
◽  
Stephen Tane Hill
Keyword(s):  
3D Printing ◽  
Selective Laser Melting ◽  
Manufacturing Process ◽  
Computer Aided Design ◽  
Design Research ◽  
Process Models ◽  
Physical Models ◽  
Laser Melting ◽  
3D Printed

<p>A common misconception about additive manufacturing (3D printing) is that any shape can be made in any material at the press of a button. The reality is that each process and material requires distinct Computer Aided Design (CAD) files that need to be optimised to the physical limitations of the manufacturing process. This optimisation process can have significant effects on the designer’s aesthetic intentions. Selective Laser Melting (SLM) is the new benchmark for functional 3D printed titanium designs where the optimisation process plays an important role in the outcome of the end product. The limitations imposed by the manufacturing process include build support material, heat transfer and post processing and designs are required to be optimised before the manufacturing process can commence. To date, case studies written on the SLM process have focused largely on engineering and functional applications in particular within the medical industry. However; this process has not been extensively studied from a visual and aesthetic industrial design perspective. This research will gather specific knowledge about the technical limitations involved in the Selective Laser Melting process and explore through a case study approach how a designer s intentions can be maintained or even enhanced when using this technology. With greater understanding of the SLM technology, the optimisation process may further provide positive outcomes to the designer by saving time, money and waste.  This case study is built on an existing product design file as a base model. Refinements to the model were made based on findings from existing design research as well as digital and physical models. The existing design research was focused on challenges designers encounter using 3D printing technologies including SLM as well as the optimisation process. Models and design iterations were developed using Nigel Cross’s four step model of exploration, generation, evaluation and communication. By iteratively redesigning aspects of the model to conform to the SLM limitations, this study reviews opportunities for areas to reduce material without compromising the design intent.</p>

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