The possibilities in Ribbon designing with CNT for Space Elevator System



This paper is a survey paper whereby we have considered the practicality and the state of art regarding ribbon design for Space Elevator system using Carbon Nanotube (CNT).


The pioneer of modern science Sir Albert Einstein once said, “If at first, the idea is not absurd, there is no hope for it” and for supporting this quotation what else could be the best example other than the idea of “Space Elevator”? In order to make space missions easier and cost-efficient “Space Elevator” is an idea of connecting earth surface with GEO (Geostationary Earth Orbit) through Carbon Nanotube (CNT) made ribbon which will be used to carry the load up to GEO altitude (Approximately 35,786 Km).(1)

Chemical Rocket vs. Space Elevator

The mammoth cost (Between the time period of 2005-2010 its approximately $ 1.5 billion per launch (2)) of conventional chemical rocket launching and the question of it’s reusability triggers the urge of Space Elevator. Even today’s reusable chemical rockets throw away almost 80% of the mass at the launch pad as consumed fuel. (2) Regarding the cost efficiency, because of the low energy consumption to move up and down the payloads it will be possible to send 1Kg of load in the orbit at less than $10 dollar! (3)

Obviously there are hundreds of questions to make this idea sounds absurd at the first hearing and the first question would be nothing but “Is there any material exists which is strong enough to hold massive load

of a space mission and lift it up to 35,786 Km altitude?” The scientists have discovered the required material for this mission. In this article we would like to discuss why this particular material is fit for this project and how we can implement it in Space Elevator Project.

Ribbon Material for Space Elevator

The total required length of ribbon depends on the available counterweight in the space elevator system. If no counterweight is used the total length of ribbon would be 150,000 Km. (1) However, 100,000 Km is considered as the optimum length for this system. (1) First two requirements for this ribbon material are – Strength and light-weight. The required strength for the ribbon material in Space Elevator is approximately 62.5 GPa (Giga Pascal). However, an allotrope of Carbon known as Carbon Nanotube or CNT has shown approximately 200 GPa of strength which is much stronger than the requires strength. If we use CNT-made ribbon the weight of total tether will be around 9.2 tons. And the diameter would potentially be 0.15 mm at the earth surface and 0.26 mm at the GEO. (3) One thing is to be mentioned here that in 1978, the legend of  science fiction literature Arthur C. Clarke in his famous book “The fountain of paradise” not only proposed the idea of space elevator even he set up 2 stage plan to implement it 1. He invented super strong monofilament carbon fibers, 2. Built a cluster of cables, then he built a solid tower around the skeleton cables.

From the above discussion it becomes quite obvious that CNT is perhaps the strongest candidate for being used as ribbon material in Space Elevator project. Now in proceeding part of this paper we will see how this CNT is formed and the possibility & challenges of using CNT as ribbon material for Space Elevator project.

CNT for Space Elevator’s Ribbon

CNT is a member of Fullerenes family which is the 3rd all allotrope of Carbon. There are two types of Carbon Nanotubes  – Single-Walled nanotubes (SWNT) and Multi-Walled nanotubes (MWNT). SWNT is made by wrapping a single-atom layered praphene into a seamless cylinder. On the other hand, MWNT is made by several grapheme sheets rolled around inside each other.(1) These nanotubes are made in microscopic level hence MWNT is a bit challenging to produce as it requires putting one rolled layer of CNT into another rolled CNT. Therefore, SWNT is the better option in Space Elevator project. We can have our ultimate ribbon by making carbon nanotube bundle of SWNTs. Most materials show their strongest forms when they are in fibrous shape. (4) The proposed ribbon will be composed of 3 mm2 cross sectional area of 10 micron diameter fibers; approximately 30,000 fibers at the anchor. (1) The interval between the tiny fibers will be 10 cm or more. (3) However, this is not economically and perhaps also technically feasible to make the entire ribbon with only CNT. In this case the best idea could be using CNT is composite. But for a number of reasons making CNT composites is not a simple task. However, In University of Kentucky, they produced 5 Km long CNT composite fiber using 1% CNT doping. This CNT doping increased the strength from 0.7 Gpa to 1.14 Gpa however, for achieving the ultimate purpose of required strength the ratio of doping has to be 80%. (1) A good example of CNT composite could be PAN/SWNT composite fiber. Even though the tensile fracture surface of Polyacrylonitrile (PAN) fiber shows extensive fibrillation however this fibrillation could be decreased significantly using PAN/SWNT composite. (5) A study showed, using 10 wt% (mass percentage) SWNT it’s possible to increase PAN fiber’s breaking strength up to 100%. (5)  It is to be mentioned here that other alternative ribbon designs have been also proposed for space elevator project. (1) We have the opportunity of experimenting SWNT composite with wide range of other materials (like PAN). Still it’s a long way to go to find out the right combination of ribbon design and SWNT composite. It’s also important to consider the challenges like lightning, meteors, space debris etc are the important risk factors in carbon designing.


The barrier between producing CNT in laboratory and implementing this CNT to build ribbon is quite challenging. However, theory says it’s quite possible what a matter here is to invent the right technique. The rapid progress on nano-techonology is quite cheering and we can hope that it is just matter of time to overcome the Space Elevator’s first hurdle: Ribbon material with nothing but carbon Nanotubes!


  1. Edwards Bradley C. & Westling Eric A. (2003), “The Space Elevator: A revolutionary Earth-to-space transportation System”

  2. Swan Peter A & Swan Cathy W. (2007) “Space Elevator Systems Architecture”

  3. Smitherman D.V. (2006) “Space Elevators: An Advanced Earth-Space Infrastructure for the New Millennium”

  4. H.D Wagner, (2003) “Encyclopedia of Polymer Science & Technology”, Available on world wide web <> Retrieved on 28th June, 2009.

  5. Byung G. Min, T.V. Sreekumar, Tetsuya Uchida, Satish Kumar (2004), “Oxidative stabilization of PAN/SWNT composite fiber”

Let’s talk money

The other day, just like any other, I tweeted a Forbes article captioned “The World’s Youngest Billionaires: 29 Under 40”. The tweet drew some serious attention, namely it put me on the radar of a friend. But the option of a 140 chars tweet-reply was not sufficient for the message she had for me (judging from the email that neatly awaited me in my inbox).


It would be impolite for me to call her strongly worded email a rant, so we shall call it an example of free speech. The content of which informed me of myself (lest I had any delusions of who I was): a greedy corporate who worshiped “those greedy billionaires”. And that it wasn’t the first time she saw such ‘shares’ from me on her social media feed. “Money” should not be the prime motivator of my life. I am bad. I am evil. I should not exist.

Thank you for your feedback, my friend. Much appreciated. You are partially right. Following Forbes listed billionaires has become somewhat of a hobby for me. Suffice to say some of those billionaires (esp the techie ones) are my rock-stars. My personal favorite ones either created or invented wonders and the “billionaire” tag just happened to be a consequence of their hard work.

Anyway, this post is not about billionaires but about the thing that made them billionaire – Money.

Money cannot solve all the problems but it does solve a lot of problems and we all know it. Certainly, “Money” is not the only reason we study and work throughout our life in modern age, but it is undoubtedly one of THE most vital reasons we pursue our academic and professional careers. And yet we feel uncomfortable talking about money. If someone says they want to make a lot of money, we question their moral standards. We subconsciously think the only way to make a lot of money is the BAD way. We doubt the rich guys. How can s/he be rich if s/he is a good person?

The purpose of my post is just to give a reminder to us. A lot of money does not always mean “dirty money”. There is absolutely nothing wrong with wanting a lot of money in life as long as we earn it in an honest and fair way. For many of us, money is not the ultimate goal; it is just a way to reach our goals. The culture in which I grew up, “Sharing and giving” is embedded in our DNA. I need money for that “Sharing and giving”. I need money to buy a decent telescope, a childhood dream of mine. I need money to buy windsurfing gears. I need money so I may perform my pilgrimage. I need money to travel to my dream-lands (Egypt being one of them-incase you wondered). Which of these are immoral or inappropriate? If none, then making a lot of money in a proper way should not be a sin too as those dreams of mine certainly need a lot of money to become reality.

To me, becoming a fan of a billionaire is just like becoming a fan of a sports player or an actor. If I am a die hard fan of a cricket player it does not mean I am going to quit my job to become someone like him. Of course I wish I could be a player like him but it’s just that, a wish. So just like that, I wish I could have a successful idea execution like those billionaires but it’s just a wish. I am not ready yet to forsake my secured monthly salary and jump off the cliff hoping I will fly. Moreover, I don’t think anyone ever became billionaire by planning to become a billionaire. And suffice to say, when I say Billionaires I mean self-made billionaires. Not the ones who are billionaires by inheritance. And again, its not the money of those billionaires attract me but the works that made them billionaires.

Five Chrome/Android Extensions/Apps I can’t (virtually) live without


If I have to be really honest with this post title, then I should write about Skype, Gmail, Facebook, Google Maps and Google Drive/Dropbox apps. Without these apps I seriously cannot live (not just virtually!) my life. But I am darn sure you are using all five of them (or at least three?) anyway, so there is no point in stating the obvious. Below are the five apps that I think can help you to live a healthy virtual life!

1. Grammarly – Google Chrome extension for word suggestion/correction:

As I average 40/50 business emails on a working day, time-wise it WAS quite difficult for me to maintain decent spelling and grammar for all those emails (+ I am not a native English speaker). Then I met Grammarly Chrome Extension! Chrome has its built-in spell-checker but it doesn’t have word-suggestion and synonyms features and thats where Grammarly steps in! In fact I found Grammarly word-suggestion and synonyms features even better than our old friend Microsoft Word! If you misspell a word, it gets underlined in red and if you just hover your cursor over that word a pop-up shows you a list of word corrections/suggestions. If you want to have synonym of a word just double click on that and a pop-up will appear.

Just install the extension on your Chrome browser and it will work on any website you visit.

2. Pocket – App and Chrome extension for webpage bookmarking:

Like everyone else on the web, everyday I come across a sheer number interesting web resources and I want some of them to store somewhere for later-reading or just archive them because they are important to me. Perhaps the easiest way to address this issue just to bookmark them on your browser. But these days most of us use multiple web devices (I mean smartphone, tablet etc) and we want to have all our bookmarks in one place. Meet Pocket. On my Chrome browser I have Pocket extension and on my tablet and smartphone I have Pocket apps. So whenever I “Pocket” any webpage from any of my devices they get archived in website. I can re-visit these stored weblinks later by going to Pocket app or website. Of course there are plenty of alternatives out there but I think Pocket’s got a  very intuitive and user-friendly interface.

3: Google translate app: You know what it is

If you are an expat like me in a country like Japan, there is a good chance that you are already heavily relied on Google translate. If you also happen to use Google translate app (I am not talking about the website) then have you updated your app recently? If have not, then do it, NOW! It has got a new great feature just last week. You can now take an image of a text (lets say a Japanese sentence) and you get the translation in your preferred language! No need of type input! Awesome!

4. AirDroid – An app from file transferring between mobile devices and desktop/laptop (Gives virtual access to your mobile device from desktop browser)

AirDroid website says “One less cable” and that’s exactly what it is! Using AirDroid I can wirelessly transfer files from my tablet/smartphone to my PC. You must be thinking, don’t we already have Dropbox or Google Drive for that? Well, AirDroid is actually much more than just that. You log into AirDroid website from a desktop browser and then your browser actually sort of turns into your smartphone/tablet (well, of course the App has to be installed in your smartphone/tablet)! Means, you can virtually control your smartphone/tablet from your browser. For instance, you can even send an SMS message from your PC as you will have access and control of your smartphone Inbox/Outbox from the AirDriod website!

5. Google Goggles – Use your images for Google Search the web

In short, you just take a picture of an object or something with Google Googles app and it gives you “Google search” results relevant to that image. Lets say I am in front of a landmark and I want to know its name. So, I can just take a picture of that landmark with Google Goggles, it will do a Google search of that landmark and return me relevant information and weblinks of that landmark.

6. And an extra one – Sky Map: Explore the night sky

If you are an Astronomy lover like me have you ever tried Sky Map? If not then just do it now! You will love it!.


Hand-picked four funny (well…at least intellectually!) TED Talks!

Like many other web wanderers, I am also an avid fan of TED Talks! TED website is my daily source of inspiration and food for thoughts! It has become sort of my daily ritual to check for new uploads in TED website at a certain period of the day. In TED curator Chris Anderson’s words “Wonder, insight, ideas – its time for TED!” (and YES, it exactly is!)

The title of this post is quite self-explanatory, isn’t it? So, without stretching the intro too far, here are my hand picked four TED Talks that I personally find damn funny yet thought provoking and/or informative.

1. Charlie Todd: The shared experience of absurdity


2. Shawn Achor: The happy secret to better work


3. Chip Kidd: Designing books is no laughing matter. OK, it is


4. Larry Smith: Why you will fail to have a great career



Random stuff I learned last week

So, here I am going to share some of the things I learned last week and think you might find them intellectually stimulating and/or thought provoking and/or mere interesting regardless of your area of interest, expertise etc. I promise to keep the discussion here brain-friendly so that the topics here can travel through the neural pathways of your brain smoothly.

1. Night sky after thousands of years: Have you ever heard of expanding universe theory? If not, don’t worry. It might sound a bit geeky but it’s not that difficult to comprehend. According to this theory, our universe is expanding, that means the distance between any two given astronomical objects is always increasing. For instance, let’s say in 2013, the distance between Galaxy X and Galaxy Y is 500 light year (light year is just a distance measurement unit like km, mile etc.). Now after 1000 years (in 3013), following this expanding universe theory the distance between those two same Galaxies (Galaxy X and Galaxy Y) will be perhaps 1500 light year (where as now in 2013 its just 500 light year)!


Image source:

No, expanding universe is not the thing that I learned for the first time last week. What I learned new about expanding universe is the fact that, the rate of the increase of this expansion is also increasing! Let me clarify. In our previous Galaxy X and Y example, in 1000 years (from 2013 to 3013) the distance between Galaxy X and Y increased from 500 light years to 1500 light years. So, the increase is 1000 light year. So, if this distance increase/expansion rate remains constant then in 4013 the distance between Galaxy X and Y should be 2500 light years. However, apparently this expansion rate is not constant rather its ever increasing. So, in 4014 the distance between Galaxy X and Y will be perhaps 4000 light year!

So, why it’s interesting? It’s interesting because after thousands of years from now (if human race still exist till then) our astronomers/cosmologists will see nothing but darkness when they point their telescope towards the heaven. The reason is obvious, because of the increasing expansion rate of the universe, all the astronomical bodies are moving away from us! Our nearby galaxies will go far away from us, so far that even the light emit/reflected from them will never reach our telescope lens anymore! Perhaps future mankind will read in the history books that thousands of years ago when mankind gazed at the sky they were able to see stars and all but that will sound more of a story to them at that point! Seeing is believing and obviously mere seeing will not help them in that case!

But before feeling sorry for our future generation perhaps we should feel sorry for ourselves! Perhaps the night sky was more interesting thousands of years ago when our ancestors gazed at it!

2. Aaron Swartz’s suicide: He was one year younger than me and he committed suicide last week. This is just mind blowing what he achieved in his short 26 years life. He was sort of a tech nerd that I always dream to be. But there is always that other side of the coin. The things made him famous are the things that lead him to suicide. You can read what he actually was here. In summary, he hacked into a paid academic journal database site, got arrested with the accusation of intellectual property violation and all those legal jargons. According to Wikipedia, at the time of his death, Swartz, if convicted, faced a maximum of $1 million in fines and more than 35 years. A lot of people are saying those legal issues were just too much for him and he took the path of suicide as an escape. Suffice to say, life must feel terribly frightening and insecure with such allegation looming over you however in a blogpost that he wrote in 2007 he mentioned about his sickness and mental depression. Perhaps allegation, depression, sickness all together caused his life but what a waste of such prodigious talent!

Semantic web was one of his research areas and that was the topic of my MSc dissertation. So many times I wished if I could be as smart as Aaron Swartz, at least on this Semantic Web field! But apparently his own smartness was pointless to him at the time of his death. His depression and fear was far more powerful than his own perception at his own talent that we all admire. We only know and care about the glittering sides of our idols. Sad. Rest in peace Aaron Swartz.

3. Word of the week: I learned a new English word this week. Sapiosexual. Sapiosexual means “a person who is sexually attracted to intelligence in others”. Anyone? :/



Michael Clarke’s Arabic tattoo and BD vs WI 2nd test day 1

By no stretch of imagination I’d say Michael Clarke & Co. read my yesterday’s post, felt a punch in the face and decided to regain their  “a team who play for high run rate in test innings” reputation from Bangladesh! At the stumps of day one 482/5 with 5.55 RR! OK Aussies. We are giving you the credit and admitting that Bangladesh is not the only team in post-Australian-dominance era who can score 4.00+ RR in a test day 😉

So, Pup (Michael Clarke) now has double double-century in this series! Of course he needs a pair of strong arms to do such of a big deal, so let’s talk about his arm :-S  (yeah I mean the physical body arm if you wonder). Just look at his left arm a bit closely.

Yes, its tattoo of an Arabic script ألم الإنضباط هو شيء مثل الألم من خيبة الأمل that’s literal translation in English would be something like “The pain of discipline is something similar to the pain of disappointment.”  I am not really known for being a big thinker and I can only read Arabic when it’s written with diacritic, so I took this message quite naively and in fact quite liked it! However there ARE people out there who know proper Arabic and also so called BIG THINKERS (I used caps lock so creatively here, I am cool 😀 ). Anyway, so the people who know proper Arabic apparently think it’s a wrong translation of that script. And those so called big thinkers say a lot of blabla on why you cannot relate these two types of pain etc.

Anyway, let’s talk about cricket a bit now. It was really eye-pleasing to watch (well, honestly speaking I just read Cricinfo live feed but we still can call it watching, right? no? :-S) Aussie batting approach today. Warner’s batting just made me nostalgic…Hayden you bloody monster, we miss you!

I did put that BD vs. WI thing in the title, but seriously what to talk about it? Now you see why I say |too” slow run rate is boring even in test cricket? I don’t think Samuels and Bravo can sleep well tonight. They just slept all day today! 😉

Bangladesh vs West Indies 2nd test: Day 1 (of a cricket fan)

…nonono, seriously, show me a Day 1 of a test match in recent past (or even distant past) where a side scored RR 4.24 at the stumps! You might be opening a new tab on your browser as you are reading it now and heading to Cricinfo statistics page just to prove me wrong (and you might prove me wrong) but establishing my argument as a fact is not my goal here anyway 😉 The naive point I am trying to make here is that, higher run rate has lately become a feature of Bangladesh test cricket! (Please don’t get started with test cricket is not about RR, it’s all about patience, consistency and all that blabla…lemme finish first!)

Now if you go to Cricinfo Statistics page and look at our recent test innings, you will see in fact we are scoring good totals these days and mostly with very healthy run rates! Suffice to say, every now and then we do have terrible (I mean seriously nasty, terrible) batting collapses, but then again compare to our early 2000’s history, we are not collapsing that often and yet our batting approach (too many scoring shots) has remained pretty same!

Let’s go back to our run rate thingy. Remember Australian test cricket when the show used to start with Hayden storm and end with Gilly thunders? We loved that! Australia made it quite usual to finish a day with 340/350. Don’t you miss those pacey test innings? Then watch Bangladesh test batting more regularly 😉

I mean look, I am not underestimating the beauty of sensible, relaxing test cricket batting with slower run rate , but come on!  End of the day who doesn’t love scoring shots! Even if there is a boundary from a thick-edge we still clap (and it happens too often to Bangladeshi batsmen) knowing how stupid and lucky the bastard batsman was!

“The end result” would be the biggest criticism against Bangladesh style test batting. But do I even need to say how many times we got “almost there” of a test win even with this seemingly nonsensical batting style!?

So, let’s just enjoy our apparently silly test batting instead of moaning over it! Of course it’s yet to bring a “REAL” test win for us, but trust me it will soon! I know bearing the pain of defeats like BD vs WI 1st test is more severe than getting ditched by your girl-friend but hey! Isn’t one “Abul Hasan’s (I am still looking for the right adjective to put here) 100” enough for believing in the future of Bangladesh test cricket? Btw, talking about Abul Hasan, please check out this Youtube video link below. Adios :)

Sunny’s warm reception to Abul Hasan after his debut century

Image credit: Cricinfo

Network effect of Semantic Web

In brief, Semantic Web is a network of distributed databases as oppose to existing web which is more of a network of distributed webpages. According to Robert M Metcalfe (also known as Bob Metcalfe),  the value of a network is proportional to the square of the number of nodes on the network. Mathematically it can be expressed as

V = n^2 (where, “V” is the value of the network and “n” is the number of nodes in that network)

Metcalfe’s law is also known as “Network Effect”. Even though initially Robert M Metcalfe formulated this law for Ethernet network however it has been implemented in other networking concepts as well that include web technology, social networking, business network and so on.

Can we can also apply Metcalfe’s network effect law on Semantic Web to estimate its value? Semantic Web is still just a vision, however we can consider Linked Open Data projects as miniature versions of Semantic Web. Therefore, by estimating the network effect of Open Data we can get an idea about the value of Semantic Web. By definition, Linked Open Data are obviously connected therefore we can consider Linked Open Data as a network of Open Data.

Now, as most of the Linked Open Data projects follow W3C Semantic Web recommendations and use RDF therefore, we can consider those individual data as “nodes” and the Semantic Web as a network. So, every time a new data or dataset added as Linked Open Data the value of Semantic Web is increasing according to Metcalfe’s law. Below is a visualisation of open Linked Data sources (we can consider them as “nodes” in Metcalfe’s law) of –

Figure: Some of the data sources of

In Web 2.0 literature, Metcalfe’s law is often used to emphasise the value of social networks. In Semantic Web, the value of the Linked Data network would be a lot more than web 2.0 (or social web) as in this case number of nodes (data or dataset) is much bigger.

If we take Reed’s law into consideration; for defining the value of Semantic Web we will get even a larger valuation than that we get using Metcalfe’s law. In Reed’s law, value of a network grows much faster than Metcalfe’s law. According to Reed’s law, the value and power of a network increases exponentially with the number of nodes in the  network;  expressed mathematically as 2 to the nth power (2n). That means –

V = 2n (where, “V” is the value of the network and “n” is the number of nodes in that network)

In Reed’s law, the number of possible sub-groups within a network also being taken into consideration. Again, social networking websites can be an ideal analogy to explain this growth. In social networks (e.g. Facebook) we can form “groups”. In Metcalfe’s law these the number of “groups” is not considered, only the number of “members” is considered. However, obviously the members can also form group within the social network and these groups can also add value to the network in much larger scale than the value created by a single individual member.

Mashup applications is a notable use of  Open Linked Data projects. In Semantic Web, we can take the different datasets from different sources and develop more mashups applications. Every time a new Linked Open Dataset is added in Semantic Web, it also adds a possibility of forming a new group with other dataset(s). Therefore, with inclusion of a new Linked Open Dataset in Semantic Web, the value of Semantic Web increases in a huge scale (2n) if we apply Reed’s law.

However, Reed’s law is not also out of any criticism. Obviously, all the Linked Data are not relevant to each other (even though technically they can be linked). Therefore, critics say Metcalfe’s law and Reed’s law overestimate the value of networks to some extent.

In one of my previous posts, I sort of divided all the Open Data projects into two categories – Linked Open Data projects (e.g. DBPedia, etc) and Non Linked Open Data projects (Pachube, DataGM etc). So according to our above discussion by applying Metcalfe’s law and Reed’s law we can say DBPedia and have more network value than Pachube and DataGM as the Open Data of first two websites are Linked Data. Now if we can transform the entire web into Semantic Web then the network effect of the web will be astronomical which will enable enormous number of new applications of the web.

Conceptual arguments on Semantic Web

Lately there has been a lot of discussios going on whether “Semantic Web” is going to be the main feature of Web 3.0 or its just an ambitious vision of Tim Berners-Lee. In this post, I am going to talk about the feasibility of Semantic Web from some conceptual perspectives that mainly includes Syllogism, AI and Godel’s incompletness theorem.

According to Shirky Clay “The Semantic Web is a machine for creating syllogism”. “Syllogism” is one of the most famous contributions of prominent Greek philosopher Aristotle in the study of logic.

A syllogism is a three-step argument with three assertions. The first two steps are called “premises” and the last assertion is called “conclusion”. Here is an example of syllogism –

1st assertion (premise): Lancaster University is in Lancaster.

2nd assertion (premise): Lancaster is in the UK.

3rd assertion (conclusion): Lancaster University is in the UK.

Even though Aristotle discussed about “Syllogism” in 300 BC however the concept of “Ontology” in Semantic Web has a direct relation with Syllogism. This becomes obvious from the example of Ontology Tim Berners-Lee mentioned in his seminal paper on Semantic Web (title: The Semantic Web)  – “If a city code is associated with a state code, and an address uses that city code, then that address has the associated state code”.

Image source:

Syllogism is an important element of Semantic Web. It helps to discover relations between resources that are true but not explicitly specified.  However, Shirky, Clay argues that, syllogism is not always useful. In real world most of the scenarios are far more complex than above mentioned Tim-Berners-Lee’s example. At times, conclusion in syllogism might be terribly wrong or syllogism might take form of Sorites paradox.

(Sorites paradox: The paradox of the heap of sand is an example of Sorites paradox. If there is N number of grains in a heap of sand and if we start removing grains one-by-one then at some point there will be only one grain left in the heap. As its impossible to decide at which point the left over sand cannot be considered as heap any longer, the last remained grain also should be considered as heap! )

Artificial Intelligence is a frequently discussed topic in Semantic Web literature. Understanding real-world context is an Artificial Intelligence (AI) problem. Even though Semantic Web concept is relatively new, however the researchers have been working on AI for quite a long time. But still AI is far away from being implemented in decision-making activities in real world scenarios. Regarding dealing with real world scenarios, Semantic Web took an opposite direction compare to that of AI. Instead of understanding complex real world scenarios, Semantic Web aims to describe the real world scenarios in less-complex way. However, as we have mentioned earlier, such simplification of real world scenario often shows terrible results. Below is an example of such consequence –

Statement 1: Mr X lives in England.

Statement 2: People live in England speaks in English.

Conclusion: Mr X speaks in English.

However, Mr X might be an immigrant who does not speak in English. There is no guaranty that based on N number of factors a system can always decide the real condition of a particular object or scenario.

Global Ontology for Semantic Web also requires agreed standards on the objects/resources. In real world, for number of objects/resources/things there is no universally agreed standards or definition. Furthermore, definitions and standards evolve or change. In small-scale it might be possible (e.g. DBPedia) to agree on common standards for describing objects however for world-wide-web-scale implementation probably this is too ambitious.

In fact, even the campaigners of Semantic Web admits the possibility of paradoxical situations in Semantic Web. According to Tim Berners-Lee, “Semantic Web researchers, in contrast, accept that paradoxes and unanswerable questions are a price that must be paid to achieve versatility”.

Godel’s incompletness theorem  can also go against the concept of Semantic Web. According to W3C’s web document “The Self-describing web” –

“RDF provides an interoperable means of publishing and linking self-describing Web data resources, and for integrating representations rendered using other technologies such as XML. The result is a single, global self-describing Semantic Web that integrates not only resources that are themselves built or represented using RDF, but also the other Web resources to which that RDF links, as well as those that can be mapped to RDF using technologies such as GRDDL” (MENDELSOHN, Noah, 2009)

However, according to Godel’s incompleteness theorem –

“…there would always be some propositions that couldn’t be proven either true or false using the rules and axioms of that mathematical branch itself. You might be able to prove every conceivable statement about numbers within a system by going outside the system in order to come up with new rules and axioms, but by doing so you’ll only create a larger system with its own unprovable statements. The implication is that all logical system of any complexity are, by definition, incomplete; each of them contains, at any given time, more true statements than it can possibly prove according to its own defining set of rules”. (JONES, Judy and WIILSON, William)      

The web has become a part and parcel of our lives. Probably, it is too late to do any new experiment with the fundamental structure of the web. One misinterpretation of semantic meaning might have serious consequence in our lives. The idea of self-describing Linked Data might be appropriate for certain Open Data campaigns but for full blown web-scale implementation a lot more research on the possible consequences should be done. The world may not be ready yet (not even in any near future) to see Pete and Lucy’s (Semantic Web) agents taking all the decisions on behalf of them as mentioned in Tim Berners-Lee’s  seminal paper on Semantic Web.

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