Dr. Z’s Corner

Dr. Z

Ahmet Zeytinci, P.E., Ph.D., Fellow-NSPE, Fellow-ASCE is an award-winning professor, structural engineer, author and mentor living in Washington, D.C. Since joining academia, "Dr. Z", as he is known by his students and colleagues, has distinguished himself on campus and beyond. He is passionate about engineering, gifted in teaching, and is a true champion for professional licensure. Dr. Z. has extraordinarily high standards; has produced award-winning designs; is prolific in professional service; and infects others with these same values. He is the recipient of numerous local, regional and national awards, including recent national awards from the National Society of Professional Engineers (NSPE) and American Society for Engineering Education (ASEE). Since 2014, he has been regularly writing monthly articles for “Dr.Z’s Corner “ and offering hundreds of engineering problems, for free, every month for students, engineers and engineering educators worldwide. Dr. Z. also offers pro-bono Saturday classes for students and engineers; his free classes are open to all in the greater Washington metro area and cost nothing, nada, zilch! Starbucks coffee is always a must have for Dr. Z.

Dr. Z's Corner

Dr. Z’s Corner (202110)

Bitcoin and Currently More than 12,000 Cryptocurrencies: A Hope or a Threat?

Dr. Eleni Smyrou

How it all started

In 2008, a novel paper was introduced to the world, titled “Bitcoin: A Peerto-Peer Electronic Cash System”, written by Satoshi Nakamoto. In this paper, a new idea was explained about a system for electronic transactions that do not rely on trust. In other words, no “trusted third party” is needed for the system to work. The physical person behind the name “Satoshi Nakamoto” has never been found and the real identity of Nakamoto still remains a mystery.

Money and the need for a “trusted third party”

In the long past, there were no monetary mediums. People in primitive societies would simply exchange goods using a barter arrangement. Bartering is the exchange of goods and services between two parties without the use of money, based on equivalent estimates of prices and goods. One of its main limitations is that one cannot store wealth in the long term.

Then came money, in the form of a shell, a metal coin, or a piece of paper that people could use as a medium of exchange, a unit of measurement of value and a storehouse for wealth. The invention of money played a significant role in the evolution and development of human societies as it allowed people to trade goods and services indirectly, providing also an effective way to store wealth. Historians believe that metal objects were first used as money as early as 5,000 BC.

The 21st century gave rise to a new form of currency, digital money, allowing digital, mobile payments. Mobile payments are money rendered for a product or service through a portable electronic device, such as a cell phone, smartphone, tablet device or a computer. Money nowadays sits in bank accounts and needs not have a physical form. Mobile payments offer the advantage that the two parties do not need to be in the same physical location for the transaction to take place. Unlike hand-to-hand physical payments by cash, digital payments can be made remotely, through a bank. The bank acts as an intermediary or a trusted third party. When Helen pays John the amount of $100.00 remotely, she makes the relevant request at a bank online. The bank needs to verify and process the transaction. It first checks if Helen has $100.00 at her disposal. If yes, it proceeds with the payment to John. It will debit Helen’s account with the amount of $100.00 and credit John’s account with the same amount. In such double entry bookkeeping, debits and credits are entries made in account ledgers to record changes in value.

These online payments need a trusted third party to act as an intermediary. Unlike cash transactions that are truly peer-to-peer, traditional online payments need to go through a bank. This can cause problems and difficulties as banks may delay or censor transactions, while in some cases transaction fees may be too high. This is the case with international payments between two banks in distant countries and especially when a third world country is involved. In addition, one needs to open a bank account to send or receive payments. There are certain requirements for opening an account and rules on who can pay and who can get paid. Privacy is another concern as a lot of personal information is revealed in every transaction and the bank or a bank employee has access to this sensitive information.

The “beauty” of cash, digital cash and the “doublespending problem”

Cash payments do not have these problems. The beauty of cash lies in the fact that there are no intermediaries. But cash has another problem: For example, when Helen gives John a bank note of $100.00, the two parties need to be in the same place at the same time. In addition, cash is bulky and therefore it cannot be easily used for big transactions. The question arises: Could we have online payments that are just like cash, i.e. peer-topeer, with no need for intermediaries, no banks, no delays, no censorship and no privacy issues? Is there a way to have digital money that behaves exactly like cash?

Many researchers had tried to deal with this issue, but they faced the so-called “double-spending problem”. Double spending is the risk that a digital currency can be spent twice. Physical currencies do not have this problem because they cannot be easily replicated, and the involved parties in a transaction can easily verify the authenticity and past ownership of the physical currency. In other words, with digital currency there is a risk that the holder of the digital currency might make a copy of the digital token and send it as payment, while retaining the original.

The solution to the doublespending problem

Bitcoin was the first successful implementation managing to solve the double spending problem. It was described as a peer-to-peer electronic cash system. The code of Bitcoin was released in 2009, after the publication in 2008. In Bitcoin, there is no bank, no central system, no single institution in the middle playing a special role. That’s why it is called a “decentralized network”. All players in this network are equal and there is no central or special player. The technology that enabled Bitcoin to make this breakthrough, is called Blockchain. Bitcoin and other cryptocurrencies, all based on blockchain technology, offer peerto-peer transactions with privacy for any amount of money, just like cash!

In a blockchain, timestamps for a transaction are added to the end of previous timestamps based on proofof-work, creating a historical record. Because the record of transactions is distributed across many nodes in the system, it is practically impossible for a bad actor to gain enough control of the system to rewrite the ledger to their own advantage. The blockchain records are kept secure because the amount of computational power required to reverse them is enormous. This technology allows Bitcoin to transfer value across the globe without resorting to traditional intermediaries, such as banks.

Bitcoin controversy

For many, Bitcoin is the ultimate democratic tool and the currency of the future. Its advantages include the following:

  • Payment freedom. Bitcoin allows us to send and receive money anywhere in the world, peer to peer, at any time.
  • Availability. It is theoretically available to populations of users without access to traditional banking systems, credit cards, and other methods of payment.
  • Total control over our money. There is no form of central authority in the Bitcoin network.
  • Security. The protocol cannot be manipulated by any organization, government or bad actor, because Bitcoin is cryptographically safe. The network remains secure even if not all of its users can be trusted.
  • Transparency. The information is fully transparent. With the blockchain, all completed transactions are visible to everyone, but personal information remains hidden.
  • Low fees. Although there are transaction fees to be paid, they are very low.

On the other hand, some economists have characterized Bitcoin as a speculative bubble or even an advanced Ponzi scheme. Bitcoin has been criticized for:

  • Use in illegal transactions. Bitcoin offers a dark medium to engage in illegal activities including money laundering, financing terrorism, collecting ransoms in hacks or cyberattacks, and buying or selling banned substances.
  • Large carbon footprint. Bitcoin is power-hungry as it is “mined” (created) using high-powered computers around the globe. Cambridge researchers claim that mining Bitcoin currently consumes around 110 Terawatt Hours per year. That’s roughly 0.55 percent of global electricity production, and more energy than the annual consumption of countries such as Argentina, Malaysia, and Sweden.
  • Price volatility. Since it was first introduced, Bitcoin has had a choppy and volatile trading history. Its price has undergone multiple bubbles in a short history. It reached an all-time high price of $64,863 on April 14, 2021.
  • Scalability problem and low speed. The scalability problem refers to the limited capability of the Bitcoin network to handle large amounts of transaction data on its platform in a short span of time. Bitcoin processes 4.6 transactions per second on average, compared to Visa’s 1,700-plus per second. For many, this is a major barrier to its wider adoption.

Conclusion and discussion

Bitcoin is a new and experimental currency in continuous development. It has many advantages that physical money does not provide to its users, however, it also has disadvantages. Various other cryptocurrencies use a consensus mechanism called proofof-stake (PoS), which is much less energy-intensive than the Proof-ofWork technology on which Bitcoin is based. The No. 2 cryptocurrency, Ethereum, is moving to PoS soon. This can solve one of the major problems of Bitcoin and other cryptocurrencies, which is the large carbon footprint of traditional mining.

With more than 12,000 different cryptocurrencies now listed by CoinMarketCap, competition between bitcoin and other major cryptocurrencies is reaching a fever pitch. Cryptocurrency is a nascent phenomenon and numerous unresolved issues still remain before it becomes close to reshaping the major shortcomings of today’s financial systems.

Dr. Vagelis Plevris
This email address is being protected from spambots. You need JavaScript enabled to view it.


About the Author

Dr. Vagelis Plevris is an Associate Professor at the Department of Civil and Architectural Engineering of Qatar University in Doha, Qatar. Currently, Dr. Plevris serves as the Chief Editor for “Computational Methods in Structural Engineering”, a section of the journal Frontiers in Built Environment, by Frontiers in Switzerland.


Dr. Z’s Corner (202105)

Civil Engineering & Artificial Intelligence (AI) Applications from Netherlands

Dr. Eleni SmyrouDr. İhsan Engin Bal

This special issue of Dr. Z’s Corner will be the last before we break for the summer. This month I’ve decided to surprise our readers and invited two well-known engineers and scholars from Europe. My guest authors, Dr. Eleni Smyrou and Dr. İhsan Engin Bal, work together as a husband and wife team and currently both are faculty at Hanze University of Applied Sciences Groningen, Netherlands. I hope you will enjoy their interesting article.


Technology is evolving at an unprecedented speed, by transforming the society, politics, governance, and professions. Civil engineering is no exception.

Computers significantly changed the way structures are engineered. The method of Hardy Cross from the University of Illinois UrbanaChampaign, for example, was revolutionary in the 30s, enabling structural engineers to design and build taller structures until the 60s. Similarly, the elastic design spectrum, proposed by Nathan Newmark who is another professor at Urbana-Champaign, revolutionized the seismic design of structures starting from the 50s. The implementation of computerized methods in civil engineering, however, was a total game changer. Now 90 years after the first publication of the Cross Method, and more than 60 years after the proposal of the Newmark Spectrum, our structural design problems are more complex than ever.

Although the civil engineering discipline adapted well to the early changes of computerization, the adoption of emerging technologies in the new millennium is slow. The use of brute-force when using computers to analyze and design larger, taller and more complex structures has become the main exploitation area of technology in civil engineering. Furthermore, structures have become much more complex in the last few decades, requiring interface with other disciplines via technologies such as BIM (Building Information Modeling), which is another technological development that found a place in practice. Apart from those, and despite the extensive research, other emerging technologies did not actually revolutionize the design and construction processes, yet; though this may change in the coming years.

Things are changing recently, although slow and limited. Some new technology applications in civil engineering are evident in the last few years. The momentum in new technologies spreading through our daily routines, and the increasing societal and economic demands, are forcing the civil engineering discipline to adapt.

In this article, we discuss one of the major emerging technologies, “Artificial Intelligence”, the magic word of the recent years.

What is AI?

Artificial Intelligence (AI) is a broader term that covers all sorts of applications where the intelligence is developed by a machine. Although the concept dates back to the 40s, everyday applications were only possible when the available computational power was enough to deploy large datasets for training models. This happened in the last several years, thanks to the use of GPU (Graphics Processing Unit), which was a major breakthrough for the realization of real-life AI.

The computers consist of CPU (Central Processor Unit) and GPU among other components. The processes are usually done by CPU and thus the computational power of your computer will heavily depend on the power of your CPU. GPU, however, is attached to the graphical unit of the computer and is used only for graphically demanding applications, such as playing videos, rendering 3D models, or playing games. Over the years the GPUs have become stronger and stronger, creating a sort of hidden power inside every computer, but used only for graphical purposes. It was not until a few years ago that it was discovered that the GPUs can be extremely useful for training AI models because they can run multiple training processes in parallel, something which can speed up the AI training significantly.

Today AI is almost everywhere. Entertainment platforms on the internet, for example, provide song, movie or series recommendations based on AI technology. The more time you spend on such platforms, the more data the AI algorithm will collect, get better trained and, in a way, get better acquainted to you. It will eventually provide you better and better recommendations. After a while these platforms become like a good friend who know your taste very well. That is the machine intelligence we are talking about.

Can AI Detect Structural Problems?

The same concept as entertainment platforms applies in almost all fields. In civil engineering for example, AI is already used in several areas. One of the most successful applications is detecting structural problems, anomalies, damage and deterioration based on photographs. Similarly to the entertainment platforms, the more data which is provided, the more accurate the model and the predictions become. Such AI-powered tools are more suitable for existing structures at the moment, thanks to the abundance of data for training models. Even if not, it is easier to collect data from existing structures rather than the new structures that are not even built yet. That is why many engineering firms are digging out their photographic databases to see if they can throw these photos into a smart AI model and replace the laborious engineering work of damage detection with computer codes.

In recent work1 with our colleagues from Hanze University of Applied Sciences in Groningen (Netherlands) and University of Leeds (UK), we showed that a simple photograph would be enough to detect a crack on a masonry brick surface. Earlier methods were able to only place the crack in a bounding box, telling us simply “there is a crack somewhere inside this box”. Our method detects the cracks pixel-wise, telling us the exact location, length, spread and width of the crack in a photograph. This was not achieved in masonry surfaces before, although AI-based crack detection is more advanced in concrete and asphalt surfaces, which are rather homogenous. Our work brings new opportunities such as regular scanning of historical buildings or old masonry structures based on simple photographs, an opportunity that will significantly reduce costs and time, and allow access to many more structures. What is superior in this method is that, even photographs taken by citizens and non-technical people can be used for extracting engineering information in a fully automatic fashion.

We support the crack detection technology with other emerging technologies, such as 3D scene reconstruction and near-infrared (NIR) crack width estimation, among others. The former is a method that can build a 3D computer model if enough photos are taken from a real structure, while the latter is a method where we developed invisible markers that reflect light only if special NIR cameras are used. Both of these technologies allow us to train a building responsible person or a citizen for taking suitable photographs for engineering purposes. Photographs can be taken regularly or after an event, such as earthquakes or deep excavations. We are already testing the combination of these technologies in a project funded by the Cultural Heritage Agency of the Netherlands (RCE).

AI is a promising concept and will certainly find further application areas in civil engineering, helping engineers make critical decisions for complex problems.

About the Authors:

Dr. Eleni Smyrou and Dr. İhsan Engin Bal work at Hanze University of Applied Sciences Groningen, Netherlands, in the Earthquake Resistant Structures research group. They both have degrees in civil engineering, as well as M.Sc. and Ph.D. degrees in earthquake engineering. Their work areas are seismic design, assessment, monitoring and strengthening of structures. Use of new technologies for structural safety has been a major research agenda topic for them for the last couple of years. They are also co-founders of “Senso Engineering – Vibration Solutions” and “Strintel – Structural Intelligence”, two startups which are providing services on the use of new technologies for structural safety.

1 https://www.sciencedirect.com/science/article/pii/S0926580521000571
(this is an open access article which is freely downloadable)


Relevant Articles

2019-20 Gold Sponsors

2019-20 Silver Sponsors