Constraint Satisfaction problem with example

 

In real life problem solving and applications, we are asked to provide the best solution keeping certain constraints in mind. Let us consider an example. Each year the National Film Awards jury has to pick a certain film as the best film of that year. How would the assessing Jury arrive at a reasonably good judgement? Do they have to watch each and every single film that year? Simple logic says that if the Jury members decide to watch three films per day it will take them the whole year (India makes over a thousand films each year) to view all of them. How does one handle such a solution demanding situation?

As with all complex problems, we need to use good heuristics in this case because evaluation of all possible entity is simply infeasible. Let us say that at the outset the National Jury need to be provided a list of best fifty films that year which can possible make the final grade. Depending on the size of various regional film industries, the selection number from that industry can be fixed and local film critics/Local Jury member can allocate scores/grades and select the best from that industry. A criteria could be set that LFSR (Local Film Score Rating) should be 0.6 and above on a scale of 1.

Similarly the apex film jury can allocate NFSR (National Film Score Rating) and based on summative score of LFSR & NFSR the best film can be chosen. We may further set additional criteria that NFSR >0.7 and LFSR+NFSR>0.8. These criteria becomes essential to filter and set standards so that the winning film is worthy of the prestigious honor.

Let us assume that the decision is arrived at through the opinion of ten jury members, five at local level represented by LJ1, LJ2, LJ3, LJ4, LJ5 and five at National levels are represented by NJ1, NJ2, NJ3, NJ4 & NJ5 …

So, now we basically have to compute the following:

Maximize (LFSR+NFSR)   where   LJ1+LJ2+LJ3+LJ4+LJ5= LFSR

&      NJ1+NJ2+NJ3+NJ4+NJ5= NFSR

Subject to       (LFSR/5)> 0.6

(NFSR/5)> 0.7

((LFSR+NFSR)/10)>0.8

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Basics about Search

  1. Why are Searching and Searching algorithms important in AI?

The operation of an AI system can be characterised as a search process in which rules are tried until some sequence is found that produces the desired solution. While selecting a sequence of operations to determine an exact solution of a problem, an AI system has to face a large number of alternatives all of which are not at all equally promising for achieving the solution. Individual evaluation of all these alternatives even with the fastest available computer requires very long time which may exceed the entire lifetime of a human being depending on the complexity of the problem.

2. What is a Search Space?

A node is a discrete point and possible goal in the solution path. The set of all nodes is the search space

3. What are Blind Searches? Why do we need to know about blind searches?

A blind search (also called an uninformed search) is a search that has no information about its domain. The only capability of blind search is its ability to distinguish a non-goal state from the goal state. Blind searches have no preferences as to which nodes it should explore first. Examples of uninformed searches are Breadth First Search and Depth First Search.

One needs to know about uninformed search as they form the basis for some of the intelligent searches.

4. What is a Heuristic?

A heuristic is the approximation done to reduce the search space.  A heuristic function defines a state in terms of a number and this number is used for decision making in the search problems.

Heuristics are used when

  • The solution path for the problem is not known
  • The perfect solution is not computationally feasible

In Best First Search algorithm, the heuristic used is the distance of the node from the goal node

5. List some applications of Heuristic search

The application of Heuristic Search fall into three general classes

  • Path finding problems
  • Two player games
  • Constraint Satisfaction problem                                                                                                                                                                                                                              6.  What is an Informed Search?

Informed Search is a heuristic search in which there is a domain specific knowledge of the search. The heuristics are used in informed search to reduce the search space. Some of the informed searches are Best First Search and Hill Climbing.

 

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Challenges before Indian private universities- 2

ASSESSING FACULTY MERIT:

It has been over a decade now that I am in the Technical Higher Education space in the private sector. All these institutes are governed by Govt. regulatory agencies. When it comes to ranking the institutes, the current practice being followed by the accrediting agencies are to accord substantial weight-age to Research and Publications. Even faculty career progression is mostly linked to the number of publications the faculty is credited with.

I have seen on quite a few instances some faculties who have great difficulties in expressing themselves flawlessly showcasing their long publication list on social media. On occasions, students have given feedback about faculties who are not too sincere about teaching in the class, but they are engaged in publishing so-called academic paper every alternate week or month. What is the casualty in all of this? No prizes for guessing the correct answer – Teaching.

It is no surprise therefore that the students who graduate from such institutes are often found lacking to fit readily into the Industry and companies need to invest substantial resources on them.

I feel if institutes are keen to survive as Centers of Excellence in the long run they need to segregate faculties into two categories: Teaching and Researchers, the expectation from each of these categories ought to be entirely different.

If we are really serious about stemming sub-quality research, which can become detrimental to the cause of real education, there is an urgent need to stop patronage of it. A report that has been published (https://www.ndtv.com/education/88-per-cent-ugc-approved-list-of-journals-are-low-quality-study-1828429) recently has exposed the fallacy of evaluating merit of faculties through such low quality publication. Teachers should primarily be evaluated for their teaching skills and their acceptability and utility in the classroom. Ignoring this could have grave consequences for the future of quality technical education in the country…

 

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What is an AI technique?

AI problem solving involves complexity. To handle complex problems, the techniques need to have the capability to deliver acceptable solutions. Some of the common AI techniques in use are the following:

  1. Learning – Learning enables to perform correctly and efficiently an already encountered problem in the past that have been solved. In a game of chess between a human and a computer, if the computer encounters a similar board position and a move by the player which led to its defeat, the computer would have learnt from its mistake and try to circumvent the situation by playing a different game so as not to repeat his failure.
  2. Heuristics – Heuristics are intelligent guesses. When an AI chess program is your opponent in a game of chess, the intelligent program must be able to infer correctly (intelligent guess) the move that you would make …
  3. Decision making under uncertainty – Driving requires reasoning/decision making under uncertain situations by the driver. A driverless car should be equipped with similar capabilities to move on the roads. AI techniques such as Fuzzy logic are often used for arriving at decisions under uncertain situations.
  4. Natural Language Processing (NLP) – Text Mining and Analytics techniques, Sentiment Analysis and NLP techniques at word, sentence, paragraph and document level, the interpretation of unstructured text data at syntax and semantic level, effective speech recognition and synthesis methodology are essential for AI systems.
  5. Embed Common Sense– Humans have an innate ability of logical reasoning. If an individual is a Ph. D. it is common sense that the person possesses an under-graduate and post-graduate degree. Embedding machines with common sense reasoning is a non-trivial task.
  6. Knowledge Based (Logic) Reasoning – Deriving knowledge / inference from a given set of facts. Feeding parametric values of a patient into medical Expert Systems may result in proper diagnosis of the ailment and enable right prescription of drugs.
  7. Swarm intelligence – For combinatorial problems i.e., problems having a large number of possible alternatives, collective intelligence in the bird and animal kingdom such as ants (ant colony optimization) and birds (particle swarm optimization) for arriving at optimized values need be incorporated for problem solving by AI systems.
  8. Case Based Reasoning (CBR) – CBR systems make use of knowledge/experience gained in the past for current problem solving.
  9. Predictive ability – Neural Networks, Statistical techniques like Regression and K-Nearest Neighbor, Bayesian Classification enable good prediction and has wide applications …
  10. Soft Computing – The ability to perform computation with imprecise data using Genetic Algorithms, Fuzzy Logic and Neural Networks or a combination of them forming hybrid techniques are widely used in several AI problems …
  11. Fault Tolerance – In many situations, humans are able to interpret intelligently even from wrong answers. As an example, India has many linguistic groups with similar surnames. There have been instances when people kept referring to ‘Mr. Das’ and ‘Mr. Bose’ and I had to infer that they were actually referring to me – Ghosh. The three surnames are mostly seen in the Bengali community and others tend to err while addressing… such capabilities need to be incorporated into AI systems…

The above non-exhaustive listing is a pointer to the widely used AI methods and techniques in recent times…

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Was Steve Wozniak totally off the mark?

 

Recently Apple Co-founder Steve Wozniak created a furore by commenting that ‘Indians lack creativity.’ As with any kind of generalizations, there are bound to be exceptions to the rule. In keeping with this, there are creative Indians who are comparable with the very best anywhere in the world… however from our rudimentary knowledge of statistics; one knows that opinions are formed from the mean value of the population & not the outliers (in this case creative Indians such as brilliant academicians, classical musicians, excellent litterateurs, painters, independent and documentary filmmakers and their ilk) who hardly enjoy wide popularity among the masses. Hence Steve must have formed his opinion by sampling the average Indians, and should he be throttled for airing his views which he is entitled to and thinks to be correct?

 

Talking about a personal experience on using facebook, I have witnessed that my friends tend to like a posting wherein photos get featured and this hardly required investing much effort from my side. On the other hand, an article that I or others may write would accrue much lesser likes … If likes dictate the popularity, creative time-consuming efforts even on a small scale hardly fetches rewarding feedbacks and appropriate number of likes… doesn’t this in a way attest what Steve is trying to tell us?…

The best way to give Steve a fitting reply would be when the ‘aam janta’ display creative choices in their lives and raise the bar for success of any product in the marketplace…let us promise ourselves to do that and within the next decade I am sure Steve will have to eat humble pie…

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Tech and Society – I

When technology is all-pervasive in this age of Artificial Intelligence and Machine Learning, Robotics and Automation, how is it impacting us in ways that aren’t on a positive note…

  1. Ability to write – The use of the shortened form of language like ‘u’ for you visible in SMS-es and WhatsApp communication is making their way even into answer scripts of the students. Students and those who adopt the shorter route fails to appreciate the beauty of those words and the language which inevitably impairs their writing ability and appreciation of the language

 

  1. Imagination & Wonderment – Einstein has said: “Imagination is more important than Knowledge.” Looking three to four decades back, there weren’t any TV around and our world was full of stories and imagination and fantasy ruled whenever we thought of them. We would visualize our heroes like THE THREE MUSKETEERS & ROBINHOOD and their act of valor through the power of our imagination. The sense of wonderment that filled the life of a child immortalized by Satyajit Ray in the classic train sighting sequence by Apu and Durga in the film PATHER PANCHALI have disappeared from the lives of children these days.

 

 

  1. Communication – When all of us are connected in various social media groups the line of separation between professional and personal lives are gradually disappearing. While I am ignorant about the situation in developed countries in the West, in developing countries like ours, in the private sector, one is expected to be in WhatsApp group of the company or available 24 X 7 on their mobile devices. Family lives of employees may go for a toss… one can’t question the escalating requirements of one’s duty lest it should appear that the employee is not sufficiently dedicated and enabling the growth of the company. After all, in most cases, the employee has a family of dependents to feed…

 

  1. Greetings and Invitation – Greetings and wishes have increased manifold in our lives. People have started sending e-card invitation for marriages. Do such invitations carry the human touch associated with Invitation Cards of yore that you received through your postal system or when the family members dropped into your houses for the invite?

I read a report in NEW YORK TIMES a couple of months back or so that Companies in Silicon Valley are complaining of Bandwidth problem because Indians are clogging the Internet with abundant ‘Good Morning’ wishes…

Recently my mother had made a request. She wanted me to buy a ‘Get well soon’ card for her sister who underwent an operation in Kolkata. Trying to comply I went into the Gift shop in our colony. It was reasonably big in terms of space and crowd and availability of items. I looked around for the Recovery card, but to my discovery, I couldn’t see a ‘single card’ anywhere in the shop. I asked the owner and he informed me that since last three years he has stopped keeping them since there are no buyers and he incurs a big loss in stocking them…not surprising since with the advent of the Internet, there are dime a dozen sites where one can send greetings for gratis. Only a fool would spend money on them. Very much like the way email has reduced our cost in sending postal mails …I returned and told my mother about what had transpired… Cards were a part of my growing up years and the thrill of receiving one after a ‘year-long wait’ for Birthdays and New Years can’t be calibrated with any yardstick…Likewise, the man who used a Typewriter to make a living and the person who had typed my post-graduate dissertation more than three decades back on the streets of a metro city have all disappeared from our lives in the age of word-processing software in computers.

A passing thought engulfed me. All of us want to live in a better society. A truly evolved society need to emphasize the importance of human relationships. Ironically, Technology that has the capacity to make life better have contributed immeasurably towards its decline …

      5. Cyber War and Cyberterrorism – seems to be in the realm of possibility and a threat facing every country.

  1. Trade and Commerce & Electronic Payments – E-Commerce and newer modes of buying and selling and making payments (web/mobile) are changing our behavior and usage of time. There exists now a mind-boggling array of apps through which one can transact. All such changes are being foisted on a nation with a large adult population averse to new technology. My mother who is a graduate with a remarkable memory and spends at least an hour every day with the newspaper asked me some days back – “Does Paytm and ATM mean one and the same thing?”

 

  1. Teen addiction to gadgets – My teenage son have been advised by the doctor to stop the use of smartphones but weaning him out of his habits is proving to be quite a job for myself and his mother. Millions of teens are caught in similar addictions and coupled with stress in their lives owing to academic pressure are getting afflicted with migraines and such ailments.

 

  1. Education – Many educational institutes are investing in automation and software and envisioning a future where the staff and even the teacher in the classroom can be dispensed with… imagine paying through your nose for the education of your child where he/she is going to a classroom with a robot education dispenser replacing the teacher in flesh and blood…

Virtual University has already gained currency.

 

  1. Fake death news – Recently I read on the Net that the famous actor Sylvester Stallone had passed away. Later I found that it was hoax news. Similarly, sometime back, the news was in circulation that the eminent director Mrinal Sen had passed away. That too was a hoax… in the pre-Internet days, one rarely came across such untruth spreading at an exponential rate …
  2. Selfies In, Autographs out – Currently Selfies seems to be a rage and people would rather click selfies with celebs rather than take their autographs as memento…

 

 

 

 

 

 

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How technology is changing our lives? – I

Yesterday Ma (Mother) made a request. She wanted me to buy a ‘Get well soon’ card for her sister who underwent an operation in Kolkata. Trying to comply I went into the Gift shop in our colony. It was reasonably big in terms of space and crowd and availability of items. I looked around for the Recovery card, but to my discovery I couldn’t see a ‘single card’ anywhere in the shop. I asked the owner and he informed me that since last three years he has stopped keeping them since there are no buyers and he incurs a big loss in stocking them…not surprising since with the advent of the Internet, there are dime a dozen sites where one can send greetings for gratis. Only a fool would spend money on them. Very much like the way email has reduced our cost in sending postal mails …

I returned and told Ma about what had transpired… Cards were a part of my growing up years and the thrill of receiving one after a ‘year long wait’ for Birthdays and New Years can’t be calibrated with any yardstick…

A passing thought engulfed me. All of us want to live in a better society. A truly evolved society need to emphasize upon the importance of human relationships. Ironically, Technology that has the capacity to make lives better (and has delivered benefits beyond comprehension) has also contributed immeasurably towards its decline …even though AI is trying to map every human emotion with their machine counterpart, I am not someone who believes that all of it can be captured effectively …

 

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