scholarly journals Stochastic stope design optimisation under grade uncertainty and dynamic development costs

Author(s):  
Matheus Furtado e Faria ◽  
Roussos Dimitrakopoulos ◽  
Cláudio Pinto
2016 ◽  
Vol 120 (1224) ◽  
pp. 375-389 ◽  
Author(s):  
H.-U. Park ◽  
J. Chung ◽  
D. Neufeld

ABSTRACTAircraft manufacturers often consider producing multiple derivatives of aircraft to satisfy various market demands and technical changes while keeping development costs and time to a minimum. Many approaches have been proposed for carrying out derivative design. However, these approaches consider both the baseline design and derivatives together at the conceptual design stage using the entire set of design variables with an assumed set of expected requirements. These frozen requirements on derivative design cannot consider new demands from market changes. In this paper, a method is proposed that uses design optimisation for conceptual design of derivatives for existing aircraft that consider requirement changes. Furthermore, the Possibility-Based Design Optimisation (PBDO) method was implemented to consider uncertainty in the aircraft operation phase. The altitude range of aircraft operation was defined as an uncertain parameter to prevent violation of constraints in the entire operating envelope of the aircraft. The PBDO method yields a more conservative design than those obtained with deterministic design optimisation.In this paper, the proposed derivative design process was applied to the Expedition 350, a small piston engine powered aircraft produced by Found Aircraft, Canada. A derivative that changes the normally aspirated engine to a turbocharged engine for high-altitude operation was considered. An optimum configuration with the new engine was obtained while enhancing performance and stability characteristics. The proposed derivative design process can be implemented on the derivative design of other aircraft.


Author(s):  
D.B. Wright

The physical features, climate and soils of the West Coast are described. Expansion since 1964 of dairy production, sheep and beef cattle numbers, and areas of improved grassland are highlighted, as is the role of the Crown in land development and settlement. While isolation and distance, development costs, river problems, and farmer attitude and knowledge are considered limitations, great scope exists for increased production by the adoption, of more intensive techniques, including horticulture on the best coastal soils, and by development of waste land.


2020 ◽  
Author(s):  
William J. Howitz ◽  
Kate J. McKnelly ◽  
Renee Link

<p>Large, multi-section laboratory courses are particularly challenging when managing grading with as many as 35 teaching assistants (TAs). Traditional grading systems using point-based rubrics lead to significant variations in how individual TAs grade, which necessitates the use of curving across laboratory sections. Final grade uncertainty perpetuates student anxieties and disincentivizes a collaborative learning environment, so we adopted an alternative grading system, called specifications grading. In this system each student knows exactly what level of proficiency they must demonstrate to earn their desired course grade. Higher grades require demonstrating mastery of skills and content at defined higher levels. Each students’ grade is solely dependent on the work they produce rather than the performance of other students. We piloted specifications grading in the smaller, third quarter course of the lower division organic chemistry laboratory series held during a summer term. Open-ended questions were chosen to gather student and TA perceptions of the new grading system. TAs felt that the new grading system reduced the weekly grading time because it was less ambiguous. Responses from students about the nature of the grading system were mixed. Their perceptions indicate that initial buy-in and multiple reminders about the bigger picture of the grading system will be essential to the success of this grading system on a larger scale.</p>


2017 ◽  
pp. 30-36
Author(s):  
R. V. Urvantsev ◽  
S. E. Cheban

The 21st century witnessed the development of the oil extraction industry in Russia due to the intensifica- tion of its production at the existing traditional fields of Western Siberia, the Volga region and other oil-extracting regions, and due discovering new oil and gas provinces. At that time the path to the development of fields in Eastern Siberia was already paved. The large-scale discoveries of a number of fields made here in the 70s-80s of the 20th century are only being developed now. The process of development itself is rather slow in view of a number of reasons. Create a problem of high cost value of oil extraction in the region. One of the major tasks is obtaining the maximum oil recovery factor while reducing the development costs. The carbonate layer lying within the Katangsky suite is low-permeability, and its inventories are categorised as hard to recover. Now, the object is at a stage of trial development,which foregrounds researches on selecting the effective methods of oil extraction.


2020 ◽  
Vol 8 ◽  
pp. 48-53
Author(s):  
I. I. Zedgenizova ◽  
◽  
I. V. Ignatieva ◽  

The relevance of the article is due to the dynamic development of modern technologies and the transition of state bodies to a digital way of exchanging legally relevant information. The purpose of the article is a brief overview of the problems associated with the regulation of the digital economy in the direction of «Digital government», as well as approaches to their solution.


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