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What is engineering and why do they need probability and statistics?

Articles > What is engineering and why do they need probability and statistics?

Te word engineer originates from the Latin term ingenerare, meaning “to invent, to create, or to regulate.” Te Accreditation Board for Engineering and Technology (ABET) defnes engineering as

"the profession in which a knowledge of the mathematical and natural sciences gained by study, experience, and practice is applied with judgment to develop ways to utilize, economically, the materials and forces of nature for the beneft of mankind."

Te layperson is ofen confused by the roles of scientists and engineers. Tis is probably because both the engineer and the scientist are thoroughly educated in the mathematical and natural sciences. Te main di?erence is that scientists primarily use this knowledge to acquire new knowledge, while engineers apply the knowledge to the design and development of usable devices, structures, and processes. Tis di?erence has been summarized— and no doubt taught to numerous introductory engineering classes—as “the scientist seeks to know; the engineer aims to do”.

Engineering in its simplest form is problem solving. To this aim engineers develop devices, processes, structures, and systems based on the application of a detailed knowledge of science (e.g., physics, chemistry, material behavior) and of mathematics (e.g., integral calculus, di?erential equations, statistics) in an a?ordable and efcient manner. Similar to economists, engineers need to understand the relationship between demand and supply, though these terms have di?erent meanings from the same terms as used by an economist. As an example, to a transportation engineer the demand may be the number and types of vehicles wanting to use a roadway, while the supply is the components that comprise the transportation system (e.g., road width, number of lanes, design standard, etc.). The transportation engineer seeks to find the best arrangement of road components (e.g., the supply) that meets the various users’ needs (e.g., the demand) and does so in an economical manner. Note that the demand and supply are not deterministic; thereby, engineers must utilize the concepts of probability and statistics in their everyday working environment.

In many ways the problems faced within the profession are similar to those faced by engineers throughout recorded history. For example, the question of how to move freight from one point to another across vast distances and over diverse geographic regions has been a problem that has attracted engineering attention for thousands of years. Approximately 175 years ago a popular method to solve this problem was the use of canals. Arguably, the most famous canal in the United States was the Erie Canal, which links the Hudson River (and hence New York City) with Bu?alo (and thereby the western United States via the Mississippi waterway via Chicago via the Great Lakes), while simultaneously bypassing Niagara Falls, which was a major barrier to movement by ship. Figure below shows a picture of a barge on an Erie Canal aqueduct in Rochester, New York. It can be seen that if the engineers wished to move freight into and out of the city, they had to frst cross the Genese River. Teir solution was to build an aqueduct across the river—in e?ect a grade separation between the canal and the river. Te aqueduct was originally built in 1825 and rebuilt in 1842; indeed, the aqueduct still stands today, although it is now used as a roadway. At the time, the construction of the Broad Street Aqueduct was a phenomenal feat of engineering, as is evidenced by Marquis de Lafayette’s proclamation during his tour of the United States in 1825:

"Te grand objects of nature, which threatened to impede, have been made only to adorn, as we see in the striking spectacle which is at this moment presented to our enchanted eye. I enjoy the sight of works and improvements equally rapid and wonderful—among which is this grand canal, an admirable work, which genius, science, and patriotism have united to construct."

Freight can be moved a variety of ways today—in containers on trucks, ships, airplanes, and railway cars. It still, of course, is moved via canals. Figure below shows a portion of a 918-meter aqueduct, known as the Wasserstrassenkreuz Magdeburg, over the Elbe River at Magdeburg, Germany. Te aqueduct was opened in 2003 and connects the Midland Canal and the Elbe-Havel Canal.

A comparison of the two figures shows that while the technology used by engineers can change, the issues faced by engineers, such as how to move freight, how to move people, and how to design the infrastructure, do not. What has changed is that we have a greater understanding of the uncertain and stochastic nature of the various variables that a?ect supply and demand. As a result, all facets of transportation and engineering make extensive uses of statistics—and without a doubt, the engineers of the Magdeburg Aqueduct did so as well. Understanding the best technologies to use, how to use them, and when to use them is not always obvious.

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