Could turning wood and crop waste into eco-friendly liquid fuel be a viable energy option?

[Partly extracted from April 14th 2011 Article in JWeekly.com]

“When we talk about renewable fuel, there are a number of issues we have to bear in mind,” says Prof. Yuval Shoham, of the Grand Technion Energy Program (GTEP).“When we’re talking about the release of CO2 to the atmosphere, which contributes to global warming, one of the relatively short-term solutions is to get liquid fuel from biomass that’s easily degradable … and the two main sources are sugar and corn,” he explained.

“The catch there is, for one, you’re using food — and it’s no secret that sugar prices have risen because of that — and also, you’re actually only using a small portion of the biomass in the plant. About 80 percent of it goes to waste,” he said. “And that’s where my research comes in.”

To that end, he and his researchers have had success with hydrolyzing wood and leftover crops — ones that can’t be used for food — for more efficient conversion into liquid fuel. But without government funding to set up plants for alternative fuel production and without a real change in the average person’s energy consumption, these solutions won’t go very far, according to Shoham.

“There’s always a fight with the traditional industry that doesn’t want change, with the car industry in particular, so some of this really does have to do with policy,” he said. “But maybe the biggest element that we can really control is education. All we’re talking here is saving energy.”

Shoham pointed to European countries, many of whose energy levels are well below that of the U.S.

“It comes down to realizing, maybe we don’t have to drive the largest cars anywhere, lights can be turned off during the day, air conditioners shouldn’t be on all the time,” he said. “All those small things, they will make a big difference.”

Prof. Shimon Gepstein and his team at the Faculty of Biology

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Plant Power at GTEP

“Our goal is to develop a platform technology for conferring new genetic traits to crop plants; such crop plants should provide a net energy gain, have environmental benefits, be economically competitive, and be producible in large quantities for biofuel production without reducing food supplies.”

It makes sense and has been done since antiquity: the burning of wood, animal fat and plant oil to generate heat and light. The scientific challenge today is to get the right plants involved in the right processes to empower our world on an even grander scale.



The GTEP group on biomass-based fuels coordinated by Prof. Yuval Shoham of the Faculty of Biotechnology and Food Engineering is applying ancient energy wisdom to modern  industrial processes. The goal is an industrial process that converts foliage and agricultural refuse into easily transportable fuels such as ethanol or methanol as shown by Prof. Shimon Gepstein’s team in the Faculty of Biology. New technologies able to increase the biomass of plants – especially those grown under harsh conditions such as in the developing world. Genetic engineering is used to develop a platform technology for conferring new genetic traits to plants that can be grown on marginal lands with minimal water supply.

You might also like: Green Power from Photosynthesis.

The Technion “Technobrain” Competition Opens 
The world’s longest yo-yo will be released from a 30 m high crane

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Prof. Seffi Naor found a way to improve online advertising sales using the auction sales method and achieve impressive results of 75% of the maximum income

Prof. Seffi Naor.

By: Yisrael Benyamini, From the main Technion website.

In the strange world of online sales, it doesn’t always pay to sell at the highest price. In order to understand why, let’s imagine a wine merchant who gets two orders: Customer A is interested in purchasing 10 bottles, at most, of Merlot or Cabernet wine and is prepared to pay $100 per bottle. Customer B would like to buy ten bottles, at most, of Merlot wine and is prepared to pay $99 per bottle. The seller checks with his suppliers and finds a bottle of Merlot. He decides to send the bottle to Customer A, who offered the higher price. Later on he finds an additional nine bottles of Merlot and sends them all to Customer A. Only towards the end of the day does the seller find ten bottles of Cabernet – except that now he does not have a customer for them and he ends his day making only $1000 in sales. If he would have sold the Merlot to Customer B and the Cabernet to Customer A, he would have made $1990 that day.

When he made his decision, the merchant could not have known that at the end of the day he would find ten additional bottles. Only after making the sale was it possible to know what decision would have generated the maximum income. Issues about which decisions to make before getting all the information are called online decision problems. In these problems every decision is liable to end up as not optimal in light of information that will be received after making the decision. Regardless of this, according to Prof. Seffi Naor of the Computer Science Department at the Technion, there is a way for the merchant to always achieve an income that is at least 63% (more exactly, 1-1/e »0.632) of the maximum income that he would have been able to get had he had all the information from the start. This number is called the competitive ratio of this method: the ratio between the results of the online method and the best results that in hindsight could have been achieved. Our merchant’s greedy method enabled him to earn $1000 instead of $1990 – in other words, a 50% competitive ratio.

Can’t wait

Some readers may perhaps suggest to the merchant not to immediately give the bottles to the customer and rather wait till the end of the day in order to decide how best to divide the bottles between his customers. This possibility does not exist in the area studied by Prof. Naor: advertising on the Internet through “Public Auction of Search Words”. In this time of advertising situation there is an Internet site on which there are ads (e.g., Google) and a large number of advertisers who want their ad on the site. Every advertiser tells the site which search words he is interested in “purchasing”, what his daily budget is, and how much he is willing to pay per search word. When a web surfer keys in one of these search words, the site presents, alongside the search results, ads that have been chosen from among the advertisers interested in the keyed-in search words: this is why this process is called a public auction.

This type of advertising presents the same dilemma that the wine merchant faced: sometimes it pays to choose the advertiser who offered a slightly lower price, so that at the end of the day, you can exploit as much as possible the budget allocated by all the advertisers.

Naor (52) completed his undergraduate studies in computer science at the Technion and his graduate and doctoral studies at Hebrew University of Jerusalem. He thereafter did a post-doctoral fellowship at the University of Southern California and Stanford University and since 1991 has been a faculty member of the Technion’s Computer Science Department. Here he focuses on the field of algorithmic theory, and specifically, on online algorithms, approximation algorithms and algorithmic game theory. Naor worked on the online advertising problem with a former student of his, Dr. Niv Buchbiner, and Dr. Kamal Jain, while on sabbatical in Microsoft’s Research Lab in Redmond, USA. Two years earlier a solution that arrived at the same ratio had already been presented but the new solution is far simpler and can be expanded to additional cases, among which advertisers also compete for the position of their ads on the page.

Good balance

In order to reach a new solution, the researchers used techniques drawn from linear programming. The principle is easy to describe: instead of the greedy method in which every time an ad is supposed to be shown, one looks for the maximum profit that can be made off of it, research showed that it is preferable to choose the advertiser who has the best balance between his remaining budget and the price he is ready to pay for the search word.

If the wine merchant had used this method, he would also have sold the first bottle of Merlot to Customer A, which would have reduced Customer A’s available budget so that the second bottle would have been sold to Customer B, who had a higher available budget. True, in this way the merchant would not have reached the amount that, in retrospect, he could have, but certainly more than he made using his greedy method. If he would have sold five bottles of Merlot to Customer A and five to Customer B, and then found the bottles of Cabernet, he would have been able to sell these to Customer B and his income would have reached $1495: a competitive ratio of 75%. There are cases in which the competitive ratio drops to 63% but never below this.

 “The algorithm presented in this research is based on a general method that I developed together with my research student Niv Buchbinder as part of his doctoral research, for a large group of online decision problems with common features,” says Naor. “The method uses techniques from the field of linear programming in order to create a formula for developing suitable algorithms. The strength of the general method proved itself when we used it to solve problems that had already been studied in the past and we obtained simpler and more efficient algorithms than the ones previously known.”

The frequency capping problem

Lately, Buchbinder and Naor used this method to solve the problem of frequency capping. This is another online decision problem from the field of Internet advertising, which was previously researched together with Moran Feldman, a doctoral student at the Technion, and Dr. Arpita Ghosh, from Yahoo!’s Research Center. In this problem, too, an ad has to be chosen such that the income for the website presenting the ad will be as high as possible. The requirement here is more typical of a content website such as a news site.

Content websites show identical pages to a large number of surfers, some of whom visit the site many times throughout the day. Research has shown that after a surfer sees a particular ad a number of times in a short period, he stops paying any attention to it – a phenomenon dubbed “ad blindness”. Consequently, many advertisers prefer to limit the number of times their ad is shown to the same surfer.

It turns out that frequency capping creates situations in which greediness does not pay off. For example, ten advertisers are prepared to pay $1 each time their ad is shown, but their budget is only enough to show one ad each day. Let’s call this group of advertisers “Group A”. Another advertiser is ready to pay $0.99 each time his ad is shown and his budget is large enough to show ten ads per day. However, he demands that if the ad is shown to a certain surfer, it must not be shown to that same surfer again the same day. Let’s call this advertiser “Advertiser B”.

Assume that initially ten different surfers arrive at the site. The greedy method would choose to show all of them one of the ads from the Group A advertisers, given that this group is ready to pay one cent more than Advertiser B. Now assume that at this point a new surfer visits the same page ten times. The first time he visits the page he is shown Advertiser B’s ad, and then the next nine times he will not be shown any ads, given that he has already seen Advertiser B’s ad (and can’t be shown it again on that day) and Group A has already used up its budget. Accordingly, the income on this day is $10.99. If we would have known ahead of time the order in which surfers would visit the page, we would have been able to show Advertiser B’s ad to the first visitors and Group A’s ads to the last ten visitors and earn $19.90 for the day – almost twice as much as the greedy method.

A greedy but smart algorithm

Of course, no site knows ahead of time in what order surfers will arrive at the site: this is an online decision problem that requires site managers to make a decision the moment the surfer arrives at the site. Buchbinder, Feldman, Ghosh and Naor’s paper presented a greedy but smarter algorithm that achieves a ¾ competitive ratio, when all the advertisers are ready to pay the same amount for an ad presentation, and proves that this result is the best possible one. For the general case, using the general method explained above, the researchers developed an algorithm that reaches a 0.63 competitive ratio, and they hypothesize that it is possible to obtain an even better ratio.

To what extent are mathematical theories such as these appropriate for real life situations? “A mathematical solution is the starting point, not the end point,” says Naor. “The real world is more complex that the assumptions on which a mathematical model is based, but algorithms can be expanded to cope with the complexity required for practical use.”

Erdos Award

Assoc. Prof. Tamar Ziegler from the Faculty of Mathematics was elected by the Israeli Mathematical Union to receive the 2011 Erdos Award. She is the first Technion faculty member to win this award. This is the highest award for Israeli mathematician and is awarded to a person not older than 40 years old who made outstanding contributions in pure or applied mathematics. 

Assoc. Prof. Tammy Ziegler

Mathematics in its prime!

Work recently completed by Dr. Tammy Ziegler of the Department of Mathematics together with colleagues from the U.S. and Britain presents a major advance in Number Theory

Dr. Tammy Ziegler

By Noam Bercovitz; http://www1.technion.ac.il/en

The conversation with Dr. Tammy Ziegler of the Department of Mathematics took place, by pure chance, on the same day that it was announced that Prof. Elon Lindenstrauss of the Hebrew University was the recipient of the Fields Medal – the most prestigious mathematics prize in the world, which is, for mathematicians, the equivalent of the Nobel Prize. Dr. Ziegler, who got her degrees at the Hebrew University, knows Prof. Lindenstrauss and his work well, and was excited and happy for him and the mathematics community in Israel. This feeling  was also reflected in the Israeli media, which proudly reported the achievement, while being somewhat surprised to note that high-level research in mathematics was actually taking place, and that Israel, as it became clear, was a major player in the field.
Dr. Ziegler has been in the Technion’s Department of Mathematics for three years. Work that she and her two colleagues, Professor Tao from UCLA and Professor Green of Cambridge University, have recently completed, has aroused much interest among mathematicians since it solves basic problems in the field of prime numbers – a mathematical field that has lately become a center of attention, after a period of slumber. The results delineate methods for finding asymptotics for arithmetic patterns of prime numbers. The solution combines methods from two seemingly unrelated fields – dynamics and number theory.

The problem of prime number pairs (twins)

The next step, according to Ziegler, involved finding arithmetic patterns in the sequence of prime numbers. The question is interesting because of the inherent difficulty in understanding the additive behavior of prime numbers. For example, many prime number pairs that differ from each other by two (called “twin primes”) are known. It is tempting to conjecture that there might be an infinite number of such pairs, but to-date the answer to this question has eluded mathematicians; it remains an open problem.
A related question that has interested mathematicians concerns the existence of arithmetic progressions in the sequence of primes. Only in 2004 did Green and Tao achieve a breakthrough by showing that the set of prime numbers contains arbitrarily long arithmetic progressions. The two researchers approached the problem from a different and surprising direction, using ideas from Ergodic theory, which is a branch of mathematics that deals with the study of dynamic systems. Green and Tao proved the existence of arithmetic progressions  of prime numbers, but their methods did not provide estimates of the number of k-term arithmetic progressions of prime numbers, all of  whose elements are smaller than N.
Dr. Ziegler’s doctorate focused on the connection between the arithmetic progressions and nilpotent dynamic systems. Prof .Tao’s interest in this work led to their collaboration. About three years ago Ziegler started working with both Green and Tao and the collaboration resulted in finding the important estimates that have aroused so much interest.

When things get complicated

Trying to explain her unique contribution to the solution of the problem, Dr. Ziegler finds it is too complicated to do in simple terms. The explanation would involve sophisticated concepts and require the reader to possess advanced knowledge of Mathematics; thus, it is beyond the scope of this interview.
In mathematical language, one of the conclusions of the work of Green, Tao and Ziegler is that each system of equations of finite complexity, or in other words, a system that is not hiding within it a problem similar to prime twins, has prime solutions unless there are “local obstructions”, and thereby corroborates a multidimensional generalization for Hardy and Littlewood’s conjectures of the early twentieth century.

With paper and pencil

It is intriguing to find out how mathematicians work, and Dr. Ziegler explains with a smile: a lot of work and not being afraid to try new ideas. Dr. Ziegler relates that her office in the department provides a pleasant and quiet environment, and sometimes in the evenings she goes to a café with a notepad and a pencil.
Her work involves thinking hard, discussions with colleagues both here and overseas in order to analyze the problem and come up with new ideas. Finally, once you get an idea for a solution, you have to try and write it out in full detail. In most cases, though, you reach a dead end, which means that a significant part of your work ends up with tossing away ideas that at first looked promising. There is also no guarantee at the start of the road that a solution will be found at its end, therefore, when you do reach a solution, such as Ziegler and her colleagues did, there is a sense of accomplishment.