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~WHDP FHY
Definition and History:
Cryptography is a method of protecting information and communications through the use of codes so that only those for whom the information is intended can read and process it. The word ‘cryptography’ was coined by combining two Greek words, ‘Krypto’ meaning hidden and ‘graphene’ meaning writing.
The first known evidence of cryptography can be traced to the use of ‘hieroglyph’. Some 4000 years ago, the Egyptians used to communicate by messages written in This code was the secret known only to the scribes who used to transmit messages on behalf of the kings. One such hieroglyph is shown below.
Later, the people switched to simple mono-alphabetic substitution ciphers from 500 to 600 BC. This involved replacing the alphabets of the message with other alphabets with some secret rules or algorithms. This rule leads to a key to retrieve the message back from the secret message.
Why Cryptography?
The goal of modern cryptography is to ensure secrecy, integrity, etc. There are many attributes of information that can be assured in this way, but here are 4 big ones:
Confidentiality: It is to assure that only the intended recipient of a message can read it. This is what most people think of when they hear “cryptography,” and it is the primary goal of classical cryptography.
Integrity: It is to assure that a piece of information has not been altered. This is the purpose of message authentication codes (MACs), message digests, and cryptographic hashing.
Authenticity: It is to assure that the sender of a message is who they say they are. This is the realm of digital signature and public-key cryptography in general.
Non-repudiation: It means to ensure that the transferred message has been sent and received by the parties claiming to have sent and received the message. It is a way to guarantee that a sender of a message cannot later deny having sent the message and that the recipient cannot deny having received the message.
Basic Cryptography function :
Encryption: To achieve this we will need a plaintext (message) and the secret key. We will use a particular encryption algorithm and give the plaintext and key as input. As an output, we will get a ciphertext(encrypted message).
Decryption: To recover the original message (plaintext) from the ciphertext (encrypted message), we will use a decryption algorithm which will be the reverse process of the encryption algorithm. We will give ciphertext and the same secret key as input. As an output, we will get an original message.
To understand this better, let’s take an example…
Suppose,
Plaintext (message) = m
Secret key = k
Ciphertext (encrypted message) = c
Encryption algorithm is chosen = XOR
So according to encryption definitely,
c = m ⊕ k
I hope you have the idea about xor operation. Don’t get confused about how to do xor of alphabets, just find the ASCII value of each character and convert it into the binary. Sounds lengthy but I hope you are thinking to write code instead of using pen and paper.
Well, for getting back our plaintext from the ciphertext…
m = c ⊕ k
You can verify this equation by putting c = m ⊕ k and k ⊕ k will be zero.
There are lots of types of cryptography (encryption algorithm). Discussing all here won’t be possible. I will just put the picture here to give you a basic idea about the structure of cryptography.
Secret key? Why it is secret?
There are two types of key encryption.
Symmetric key encryption: in this case, the key used for encryption will be the same as the key used for decryption.
Asymmetric key encryption: in this case, the encryption key and decryption key will be different.
Note: the example we took above is symmetric key encryption.
Why do we call this key a secret key?
Obviously, it has to be secret. What if it is not secret?
Suppose there are two persons Alice and Bob wants to communicate secretly. Alice encrypted a message and send that ciphertext to Bob. There is an eavesdropper Mallory who will be able to see ciphertext. Now, if the key is not secret, Mallory can perform the decryption process and get the plaintext. So the communication will no longer be a secret.
CONCLUSION :
This blog contained history and fundamental information about cryptography. Covering everything in a single blog is not possible but I believe it was a good kick start.
Talking about the nonsense I wrote at the start of the blog, I have encrypted it using Caesar Cipher. If you wanna know what is the meaning of that you can decrypt it using this online tool: https://www.dcode.fr/caesar-cipher
If you have reached here, you are definitely intrigued to explore ways you can enhance your humble typing and get that much needed touch typing skill added to your accolades.
Its a subtle confession that when we see a developer typing his code into the terminal or an editor at blazing fast speeds, we all feel awe-inspired and amazed and just gawk at the marvel. If you are one amongst us who have always wanted to get better at typing but just don’t get the way of getting started then I guess you should be getting prepped up as the content coming ahead will help you do exactly that.
But before anything, one Important point that I would want to discuss is the plan that we will follow while learning “how to type — blazing fast!!”.
Some months ago, I came across a YouTube video. It is a short 20 mins Ted Talk by a man named Josh Kaufman who is essentially telling us about his research in which he reveals the secret of Learning anything in just 20 hours. I would highly recommend the reader to pause and watch the video before moving on with the story. It is a true treasure!
Well, hope you did watch the video 😛
Josh tells us one important thing that we often tend to forget :-
We are often not preparing to be the best in our field of learning. Most of the time we are just preparing to get good at that one skill.
It is quite important to understand this concept. I have had many personal experiences myself in which I have procrastinated learning a skill, just for the fact that it seemed really overwhelming at first. I used to evaluate the learning curve in my mind and believe it to be very steep as if it would drain my soul equivalent to climbing Mt.Everest. I guess we all can share that feeling. Such thoughts often come to our brains when we are thinking of learning a new tech that’s blooming but completely new to us.
Well, nowadays it gets really easy as I know that in order to get just good at something I need to invest only 20 hours into it. Nothing much is expected from me and I can make myself reliable enough in just 20 good learning hours and that makes the process much more relaxed and in turn really rewarding.
Moving on, I guess with all that background score already set up we can comfortably look into the learning at hand here.
Touch Typing
Photo by Fabian Irsara on Unsplash
Learning typing should be taken as a very basic skill and I feel it is much equivalent to learning to write your first alphabet letters by hand. You have to remember the key positions, get them into your finger memory and then practice practice practice until one day you know that you are able to glide in finesse on your keyboard.
Allow me to break the learning into two parts.First one will be memorising the key position and positioning your fingers on your keyboard in the most efficient way. Next comes the never ending practice!
Memorising the key positions:-
There are so many websites available online that teaches you this. My personal favourite is typing.com. That maybe because it was the first site that I reached when i thought of learning typing or maybe because of the great User Interface that they provide that eases the learning process into a very intuitive one.
User Interface for typing.com
After making an account as a student, you will be taken to a page where you can see lessons that will help you getting started just like that. Start by learning the key positions, how to place your fingers on the home row and how to use your thumb for the space bar.
As you will practice more and more and complete the lessons you will progress from beginner to intermediate and later to advanced. This can feel a bit overwhelming at first while you read it but let me show you some calculations that will help getting clear with the learning plan.
We know that we are preparing for 20 hours. That means 1200 mins. If we even invest only 10 mins into learning typing everyday we see that in just 120 days we would reach our goal. 120 days is more or less 4 months.
So you see, in just 4 months with daily practice of 10 mins you will earn a feat that will give you all that nerdy feel with a typing speed that will easily reach to around 70 -75 words per minute. Lets move on to the next phase of our process.
Practice and polish your skill:-
Once you have attained that finger memory and know how to locate keys on the keyboard, you now need to practice, practice hard! so that you can generate speed into your dexterity.
keybr.com is a great place built exactly for that. Quoting the developers from keybr-: It employs statistics and smart algorithms to automatically generate typing lessons matching your skills.
It helps you find your weaker keys and shows them on the screen in red so that you can contain your focus on them while you type. It also auto generates its lessons such that you are given more opportunity to improve on your weaknesses.
Keybr is a great place to practice and ease finesse. With all that data they take from your typing sessions, they generate many graphs and visuals that you can refer to and also download from the profile section. You can also compete with other typewriters in real time in the multiplayer section. And the best part, they also have a dark mode. Isn’t that amazing : D
Learning how to touch type is a great skill one can learn. It helps you write your code fast, your documents fast, helps you to amaze your friends by yours subtle finger-dance on the keyboard and vert importantly — stand out in the crowd.
Also, just as a proof to my learning, here is a screenshot that shows my present typing speed on keybr. Mind that I did start learning around some 3 months ago and have reached here with just 10 mins everyday.
“Avinash is a Senior Undergrad at NIT Surat, a person who has profound skills in the field of Frontend Engineering. For any kind of query or doubt, reach him out at Linkedin“
Following is a blog prepared by taking the discussion CEVians had on 09 Sept 2019 as foundation and motivation.
The topic of discussion was “CURRENT STATUS OF INDIAN ECONOMY”.
If you are in a hurry and at any rate dont have time to cudgel your brain to understand this gigantic scenario then you are at the right place, just keep plugged. CEVs editing team do consider the people with big dreams that don’t have much time to know the affairs out of their domain. Just like you, we understand how critical it is -to know these things in an individual’s life and also -to determine your role as a participant of the Earth’s largest democracy.
So let’s begin with some numbers just to get all the readers on the same page.
SOME CRUCIAL NUMBERS AND FIGURES:
The GDP (Gross Domestic Product) of India bars at $2.972 trillion with a growth rate of 5.0% in April – June quarter, the first quarter of the fiscal year 2019-20.
In 2019 India slips to 7th largest economies from the 5th rank in 2018.
India slips to 7th position from the world’s fastest-growing economy in 2018.
Unemployment rate is at 7.91% in June 2019.
Five of the seven key sectors are witnessing slowdown or creeping growth rate:
Automobile sector is at a negative growth rate of -30.9%.
Textile grows at nominal 1.66% rate
Agriculture sector shrunk by 0.3%
Manufacturing is growing at 1.2%
Mining sector has a growth rate of 1.6%
Power generation, however, grew at a good rate of 8.2%.
Real Estate’s unsold inventory stands at 42 months, the healthy number is 8-10 months. The number of unsold houses has increased from 1.20 M in 2018 to 1.28 M in 2019, a seven per cent rise.
FMCG (Fast-moving consumer goods) companies like Hindustan Unilever, Patanjali, Britannia, Asian paints, Dabur India all of them dropped volume growth from double digits to a mere single digit.
The PFC (Private Final Consumption) is at dead low at 3.1%, which hung at healthy 7.2% in the previous quarter.
The new project announced including the public and private showed up a massive drop by 79.5% from the previous year.
Now all I want is to not get dejected by looking at these ugly numbers. It’s better to know hard truths than been pleased by bluffs. There are so many opportunities for India to get back. For that we need to understand from the scrap what exactly is pulling Indian economy behind and what needs to be done exactly.
WHAT DO THESE NUMBERS ACTUALLY INDICATE?
1. “Gross Domestic Product (GDP) is defined as the total monetary or market value of all the finished goods and services produced within a country’s borders in a specific time period. As a broad measure of overall domestic production, it functions as a comprehensive scorecard of the country’s economic health.” – Book definition
Now, the Indian GDP is falling for the last five consecutive quarters.
The current rate is 5% which itself is disheartening but question have been continuously been raised over the data and reputed economists like Arvind Subramanyam and Raghuram Rajan suspects that actual figures might be even 1-2% less.
However, if we see GDP on a larger time scale we can figure out that the GDP of India in fact any country is not a constant number rather is cyclic throughout the fiscal quarters. And this effect is multiplied in India because of having huge diversity in markets.
It has been a little long time since the GDP is falling but we cannot conclude that India’s economy is in deep trauma by just seeing dropping GDP.
2.Unemployment:
NSSO (National Sample Survey Office) report says that the nation in 2017 went to 45-year high unemployment rate @6.1 %, which in July 2019 touches @7.91%. However, Govt denies the credibility of the survey, following which two non-official members of National Statistical Commission (NSC), its acting chairman PC Mohanan and Mrs JV Meenakshi resigned. Now, this number is also cyclic with various seasons in India but such high % really puts a big question mark on the health of the current economy.
3. a.) Automobile Sector:
Many key sectors are not performing as they are expected. Most shocking numbers are of the automobile sector which has seen the highest negative growth rate in 19 years, last was @-35.6% in 2000.
The sales have been on a decrease for the last 13 months (since July 2018).
The Indian auto industry has a contribution of 7.5% to GDP and with a workforce of massive 37M, in both informal and formal sectors. The negative growth has made 2L job loss in the last three months only and projections say that shedding of up to 1M job in near months and quarters.
However, the auto sector was destined to this slowdown one day. It has its own reasons and other contributing factors too.
The raising Global warming concerns have made both govt and consumers lose confidence in petrol and diesel automobiles. Electric Vehicles, on the other hand, finding it too hard to penetrate the market due to technical and infrastructural issues.
But no one had expected such a sudden collapse, which indicates to some other contributing factor playing roles behind. Those factors would be explored as the discussion moves forward.
b.) Manufacturing Sector:
This sector was growing at significant 12.1% in Q1 of the 2018-19 year and in Q1 of 2019-20 fiscal year, it has dropped to shocking 0.6%. This dip majorly comes from the auto sector slowdown as it comprises of 42% of it. Overall industrial production has dropped massively from the last year. This drop-in production is not due to lack of resources or the shortage of labour (either skilled or unskilled) but it is rather weird. The market has full reserves of various products but the sellers aren’t able to find customers to sell them rather. Keep reading, the mystery of this slowdown will unfold soon.
c.) Agriculture Sector:
For decades agriculture has been the backbone of Indian Economy and still continues to be by providing a living for half of the pop. Literally, no one escapes from catastrophe if Agri is weak for a quarter or some. National Council of Applied Economic Research (NCEAR) a non-profit Delhi based economy think tank said in a report that as of August 2, 2019, 12 agro-metrological subdivision out of 36 in the country were rain deficient further adding that in 2019-20 the real agriculture GVA is expected to grow at 0.00%. If you didn’t get the meaning than knowing the fact that we had 5 major and numerous small farmers marches across the nation in 2018 would help you understand the situation a bit.
Indian farming is under distress due to depleting water table, extreme climate and unpredictable monsoon, and declining productivity for decades.
Crop prices are stagnant for years at minimal. Rarely farmers are getting more than what they put in, the declining rural wage is evident.
The rate of increase in farmer suicide is haunting.
Listening to the stories of farmer protesting by carrying mice in mouths, skulls of their dead mate, and 100-year old fasting for over 40 days are things we must have avoided to happen, for the god sake.
It’s pretty hard to understand why high profile figures died of personal problems find their way to be in the headlines for days but the 296438 farmers (1985- 2018) who chose to drink pesticide or something to kill themselves hardly find a space in the last page of a newspaper column even RTI activists have to struggle to get data only.
Published on 08 Jun 2018 in scroll.
d.) Textiles:
The textile industry is the second biggest employer after agriculture with a total workforce of 100 M and contributes to 5% of our GDP. Thereby making India the largest cotton producer on earth. However, the spinning industry is struggling for a long time with profitability. The industry has shown a mere growth rate of 1.66% in this quarter.
Now you might have thought that you visited the mall last time you didn’t compromise on new clothes in any way. Then what wrong here!
Export went 34.5% down this year quarter than the previous year’s.
The NITMA (North India Textile Mills Association) was feeling neglected by agencies and thus used quite a weird approach to say their word. On 20 August 2019, they published an advertisement in a newspaper “INDIAN EXPRESS” to draw the Govt attention towards the severity of their current status.
They claim that 1⁄3 of India spinning capacity is already closed and those which are running are also under great loss. And this newspaper clipping alone is enough to say a thousand words on the current coordinates.
4. REAL ESTATE:
Contributing to 13% in GDP and employer of 55 M. The real estate caters a spectrum of industries in itself from the on-site construction to brick, cement, steel factories. We have masons, plumbers, electricians, engineers, architects, builders, brokers and a range of other professions forming a massive chain of employment.
And even this sector is not so profitable as far as past years and current situation are concerned.
A report says:
“Over 12.76 lakh houses are lying unsold in India’s top 30 cities. The inventory overhang is as high as 80 months in Kochi, 59 months in Jaipur, 55 months in Lucknow and 72 months in Chennai, implying it will take between five and seven years for developers in these cities to get rid of the present housing stock.”
This industry is mainly in slowdown due to implementation of govt visionary reforms like RERA, GST and others.
5. PFC:
Here is from where you can explain all the sectoral slowdown.
India is a nation of 1.32 B hearts, the market is huge, and thus the inland consumption contributes to 50% of the Indian GDP. Though the nation is not a mega exporter still our own demand drives the economy. We have 70% of the Indian population comprising of rural folks, and currently in a phase shift from low to the middle class. And this is from where major demand comes from. You won’t expect huge continuous demand from middle-class society than from transforming rural low-class society. For example, when was the last time you saw someone purchase a new washing machine, fridge, etc in your society (located in a city). The answer is “a long time ago”, and this is called the middle-income trap.
Now you must have noticed how strong focus is laid on the agriculture and textile section in this post. The declining rural wages are forcing a large section of consumers to postpone their expenditures. Hence leading to the demand-side crisis.
Now the question is what actually happened to them?
REASONS FOR THE SLOWDOWN
Demonetization: However, some reasons are deep below but the demo was the event that began the chain reaction. Banning of high value 500 and 1000 Rupees notes on 8 November 2016 sucked 85% of currency from Indian markets. With a multispectral vision to squeeze black money, to promote digitalization and to stop infiltration on borders the govt merely achieved any of its goals but surely the event triggered a sequence of mishaps that has taken an ugly face now.
Farm prices began falling as the consumers were not able to buy the produce due to non-availability of cash.
Even though the demand was good in the market but demo had severely limited the ability of agricultural traders to buy produce from farmers.
Dramatically prices fall and farmers have to literally throw away the produce on roads.
This persisted for a long time and hence led to distress in agriculture sector triggering everything to come off track slowly.
That 70% of the population we discussed earlier stop making demands, and slowdown began.
But what happened to the urban sector, why it is also slowing down?
The clue is in the auto sector slowdown. We saw how cars and 2- wheelers sales have fallen, but on the other hand sales of trucks and commercial vehicles have also fallen and quite significantly. This is evidence for the fact that demand has really come down magnificently hence the transportation resources are not required anymore. Even IR have seen a decrement in rail freight, a tribble and horrible sign. At this point the rural problem transmitted to the urban scenery.
Various industries started slowing down production and to maintain their economy began shredding jobs.
The casual workforce available in the market became abundant and competition turned fiercely.
Consequently, the wages rate of casual labour came down and major urban demand driver halts.
Completing the loop which will soon bring the whole economy on knees if the government doesn’t take charge immediately.
THE GLOBAL SCENARIO:
Few parameters are determinant in indicating the status of the Global Economy. Let us have a look at some:
1. South Korea is a major exporter in the Asian continent products ranging from Electrical Machinery, Computer chips, Vehicles, Plastics, Medical apparatus, Iron, ships, etc have seen a dip since early 2017 and it is still declining @-13.6%. Which clearly indicates that the world is becoming a less open market.
2. Copper is used so ubiquitously from the household wiring to autos, TV sets, etc. The world’s largest exporter of Copper- Chile has seen a dip in exports. Indicating the slowdown the whole world is impending to. With overall auto sector slowdown on a global scale as govt across the globe continues to ban diesel cars in cities consumption of copper have decreased.
3. JP Morgan’s Global PMI (Purchasing manager index) tracker which show the health of manufacturing around the world, shows a declining graph from early 2018.
4. We are having big problems of extreme weather, climate change followed by nation backed cyber attacks and above all is a stand-off between the two nuclear states. These incidents give a whole lot of a reason for Global Slowdown.
WHAT DOES RBI ANNUAL REPORT SAYS:
Since we have promised to keep this short so interested readers take their own efforts to go through the detailed RBI Annual report, which cover various aspects of current scenario more vividly.
The numbers do indicate that the economy is in trouble but we need to be optimistic and we must not panic. The demonetization took a hard hit on the backbone of the Indian economy i.e. agriculture. The dropping rural wage has immediately stopped the demand in all sectors including the FMCGs. The rapid rolling out of visionary GST, RERA, IBC, NBFC, MERGER had somehow hammered the investor’s faith and trust and had plotted a fear leading to the real estate slowdown.
On the other hand, it is a stroke of awful luck that the global recession had coincided with our slowdown, which had a multiplier effect.
THE CEV WAY FORWARD
Cutting the taxes on automobile sector might not make a major difference, instead, somehow the consumers are needed to be enabled to make demands, which is only possible if they have money in hands.
The Government needs to put its money to build rural infrastructure (roads, schools, shopping complex) by assigning the project to small localised builders in the region. Which will in turn not only directly put money in the hands of the 70% of the population but also increase the economic activity in those areas.
The 3000 Cr spent in constructing the statue would have been instead used for the renovation of rural public properties like roads, community buildings would have more beneficial in both the short and long term.
MNREGA continues to languish and govt needs to focus to increase employment as well as wages. This will again be returned to govt as increasing economic activity will increase the tax collection also.
Various other fixes can be used to tackle this slowdown but we need to do a lot more to avoid such slowdown in future. The load on agriculture need to be less burdened. (The core reason of slowdown). There is an urgent need for massive employment. All of this is only possible if India pushes to become a manufacturing giant because the situation would have been diverted if we were good exporters. Manufacturing requires a rock-solid modern education system.
We spend a mere 1.8% of GDP on education in an era when the world average is 5-6%. (This also include mid-day meal budget!)
We don’t have any university or institute in world’s top 300. IISc at 301.
Less than one percent of students in higher education level are research scholars, the majority are just pursuing a BA degree in Arts, history, etc to just become graduate.
Stray animal walks into the classroom of nation’s topmost engineering college.
The government needs to be very definite in rolling out anymore reform and have to work in some way to establish trust in citizens again. It needs to empower the rural folks and give oxygen to the economy by pooling some money in rural India. Simultaneously we need to work out old melodies also. Education, health, quality of life, etc. all of this matter in a nation building.
Contrary to that the need of the hour is not just nation to develop individually rather the time requires all of the nations to play their crucial international roles. Global winds are challenging every economy around the world. WEF (World Economic Forum) reports say that 9 out of 10 economist expects the economy to worsen due to the rising geopolitical tensions.
At this moment the world needs to hold each other hand tight and push for a little better tomorrow.
Yes! Yet another out of the blue abstract topic in the house…. We were amused by the selection of such an abstract topic . Obviously we had done no preparations and had no clue about it.
So as the discussion started, the first thing which struck us was about the shape and the size of the cloud. We remembered during our childhood days, visualizing objects from our daily routine while watching clouds. While on a sunny day, observing the white clouds and evoking the imagination within us. Clouds are an important part in a scenery with lush green fields.
They depict the two sides of human nature, the light and fluffy showing the joyous and blissful nature and on the other side are the dark and ugly clouds showing the negative human nature .Clouds bring hope for farmers while on the other hand they bring grief for people not having concrete houses.
Clouds too analogs with the human life cycle. They have their birth from the water evaporated from oceans until it rains to accomplish its existence. They serve the mother earth with rain just like humans serve to the society to show their existence!
Clouds are seen as the visible limit to the sky. They act as a blanket to the planet earth. On a sunny day ,during the summers playing cricket on the fields, whenever a cloud provides us with a shade we silently bless them to stay and protect us from the harsh sun. If the sky is a window then clouds acts as a curtain, this inspires us to raise the curtains of our life and widen our vision.
Clouds are commonly used in literature showing the aspect of freedom. They motivate us to cross our personal boundaries and limits as clouds float high in the sky.
One of the most peculiar thing about clouds we observe is that it is often perceived as a storage unit. Practically it can be said as a storage for water droplets. But we often notice on comics or animation that thoughts of a character are showed in a bubble or cloud!! Also the famous Google cloud or I cloud storing our data!! So indeed it’s one of a kind..
Clouds are even worshipped in countries like Sweden and Norway! They glorify scenes in cinematic performance as in the Oscar winning movie La- La Land.
Clouds can be a beauty as well as a beast .
Clouds can be romance for poets or a canvas or artists.
In a nutshell, we can see clouds as two visions- one as the scientific eye i.e the concept of water cycle and how clouds help in growth of various crops,etc. Other vision is the imagination part where clouds can be seen as a plain canvas which can be filled with an unlimited imagination of ours. For some it can be considered as a figure of freedom and for some it can be as a figure of boundation, all depends on each and every person’s perspective!!
Reading Time: 4minutesMinutes of the Group Discussion- CEV Date- 29/08/19
Yes, you read it right… The topic for the group discussion was Zero!! We had a similar kind of expression when the some CEVians put the topic on the table. We were stunned by this abstract topic and Zero was exactly the number of thoughts maximum of the participants had about the GD. What made this GD special was how spontaneous and creative it was. No one had a clue about the topic which meant no time for preparations and study.
As the discussion started, the first thing that popped on most of our minds was about the inventor of Zero, Aryabhatta.
Aryabhatta has published a lot of work in the field of algebra, an approximation of π, etc. But he is primarily known for his work in providing us with the wonder number Zero! It was evident that Aryabhatta opened up a lot in the field of mathematics, but also left many mysteries for us to unlock. For instance, we know that zero is that number if we multiply, the product is zero again. But still can’t determine what is the answer if we divide any number by zero.. Clearly he gave us something, whose applications are not that easy to interpret. There were talks about the physical interpretation of the number Zero. The word zero is translated to śūnya (Sanskrit: शूय) in Sanskrit which interprets as a sense of nothingness. And maybe that’s how we understand zero as in a physical way. We often see people referring others as HERO and ZERO. That zero is implementing that the person is nothing in comparison to the other. Also, we have seen a movie named “Zero displaying about a person with fewer abilities in comparison to others.
So in all, we can say that the term zero has a very negative physical interpretation in our life. Things got a little philosophical when we all tried to step into Aryabhatta’s shoes and determine the reason behind the shape of the mathematical notation 0. Was it because he predicted the motion of planets around the sun? Or was it something to do with what he saw in real day to day life? Well, this reason died with him many years ago.
The discussion was swayed to applications of zero! Zero is probably one of the most important discoveries of all time. Before it’s discovery people rarely used numbers for anything beyond counting and so zero was not really required. You either had a sheep or you had none. But now we have evolved into a much better world with zero. We live in a world of computers which would not have been seen if not for zero because of its contribution in binary language, which is the language for computers. Zero has a wide application in the field of algebra and quantum physics too. Zero is considered as a base level for many concepts which build on to give many significant things in the world. As we know, zero is the point between positive numbers and negative numbers i.e zero is between positivity and negativity. Applying this analogy to life, zero can be considered the origin of new ideas and thoughts which can push the person in any of the two directions which eventually decides the fate of a person’s future. Clearly we can see that zero has various applications in many fields, but there are very limited applications of the real meaning behind the term zero. Zero was coined to the sense of nothingness. There is almost no use of this sense in most of the applications of zero. Most applications work under the feel of assumptions. For instance, in the binary language, it was assumed that 0 and 1 will be the two things that the computer understands. If something else would have been assumed earlier, the world might have worked out the same. So while there are many applications of zero, the application of the essence of zero is still limited. In a nutshell, when we thought there was nothing more to say about just a number, a few many things popped up. If mathematics is a spear, zero may be the sharp tip of it. To end I would like to say, zero is nothing but everything.
Reading Time: 8minutesTeam CEV had a group discussion on “WATER CRISIS” on 6 Aug 2019.
Let us begin with the question very less addressed, “does debate or GD of any kind ranging from the news channel debates to the general public discussion actually lead us anywhere?”.
Introverts might say certainly nowhere!
Even those who actively participate in the debate have a fuzzy view that whether it would lead them to a practical conclusion. For TV anchors with radiant communicating character, it might be a source of income, for the general public it might be a casual routine just for the sake of time-pass, for a student chapter it might be an activity for improving comm. skills.
Being a pro-debate enthusiast if you got annoyed by the statement that debate rarely leads us somewhere than pick up any worldwide issue and just find out debates and discussion on that topic, you can list a thousand. At the same time, concerned problems remain as it is, for example- global warming, poverty, malnutrition, and crimes, etc.
But before we arrive at the conclusion that debates are worthless, just wonder for a while over what led to the rapid success of NASA in space in the late 1960s. Of course, it was due to motivated men and women of the organisation. Do those folks got their motivation by watching motivational videos of speakers like Mr. Sandeep Maheswari on youtube. Might be, but not wholly. The real fuel was those instants when individuals got dreams in their head while listening to the people around them applauding the astronauts and scientist, they watched TV science shows and reports which ignited in them a fire, which later the world watched!
In those days the scientist were heroes and they gave public lectures at scale in which we attend concerts these days.
So there is no doubt that science discussion are cradle for scientific motivation and temper as well as for future cutting edge technologies.
WHY WE CHOSE “THE WATER CRISIS”?
Because it is the most critical and wide-spread issue citizens are facing pan India.
Realizing the danger:
1. As per the report of NITI Aayog, 600 million Indians faced extreme water stress and about 2,00,000 people die every year due to inadequate access to safe water.
2. Twenty-one cities, including Delhi, Bengaluru, Chennai, and Hyderabad will run out of groundwater by 2020. While currently 12% of the population already lives in “DAY ZERO” scenario.
3. The present condition of the villages is poorer. Villages in India are grappling with a severe drinking water crisis, with no water left in 35 major dams.
4. The Groundwater which is source of 40% of India’s water needs, depleting at a rapid rate.
5. It really puts question mark when we hear the news that “the wettest place on earth ‘Cherapunji’ suffers a water shortage”, one of the greatest irony of the 21st century.
CEV members finally classified the major reasons behind India being thirsty into three categories:
THE IGNORANCE
Well, there is no doubt that we are very ignorant while using water. And if you see the statistics then you would feel that “ignorance” fails too short as a word to address us.
1. Study says India waste 30-40% of the water through leaking pipes. Kolkata stands apart with 50% wastage and cities like Coimbatore, Mumbai, and Delhi are doing quite good with 40, 25 and 18% wastage.
2. The efficiency of irrigation and that too with fresh ground-water is about 35%. We need to think why a country which boasts of producing greatest intellectuals in world drain about 80% of household water to the sea and small war-affected countries like Israel reuses 90% of domestic water.
Being the largest sector in water utilization, improving the efficiency in irrigation is the most promising way to cut down the use of water significantly.
3. How many of us would close tap if we see it open in surroundings, how many of us empty the half-filled bottle to fill it again, how many of us use showers than buckets for bathing, how many of us tap water from ACs and ROs, how many of us have rain-water harvesting at home and finally how many us play holi with water. Answer to all these questions clearly indicated we aren’t serious about the water crisis, and we feel the extreme ownership of water just because we paid for it.
TECHNICAL ISSUES:
Water is a renewable source and also it doesn’t get evaporated from the earth and escape to the vast space then why the hell is this water problem. With 7500 Km of coastline we have access to nearly limitless water supply from oceans, why don’t we use that? Salty ocean water is not potable for common use and is made available by nature through rains. If we try to mimic it by using current highly energy-intensive processes like desalination than our country will be like burning all of its coal for processing ocean water.
GLOBAL WARMING AND ENVIRONMENTAL IMPACT
1. Just after a speedy recovery from the devastating floods of August 2018 Kerala set for a severe drought in June 2019.
Through this phenomenon, we can understand the impact of climate change on the availability of water in the shortest observation period. We don’t need to turn a research paper to know that climate change can impact the water cycle in ways that can lead to the destruction of all lifeforms.
2. Glaciers are rapidly melting turning the freshwater to salty ocean water and flooding the coastal regions.
3. Eutrophication and Algal bloom: Many of you would have seen an abandoned green layered lake or pond near your locality. That source of freshwater turned into a toxic pond due to an exponential growth of harmful algae, as the fertilizers from crop field sweep to that pond. Sometimes the effect is so enlarged that whole river or part of sea becomes a trap, like the Arabian sea.
MANAGERIAL ISSUES:
1. India ranks highest in the world in terms of siping groundwater, and not marginally by competitors. The second and third ranker combined fails to sip water as much as India.
“This kind of use has caused a reduction in groundwater levels in India by 61 percent between 2007 and 2017, according to a report by the Central Ground Water Board (CGWB), presented in the Lok Sabha last year.”
We are not stopping here, it is so unfortunate when our dear elected ministers pass the bill to build borewell in numbers as that of stars in the night sky. “The Bihar government announced to give water to every village. For that, they started building borewell across the state which led to the depleting amount of water table. As per the survey, there is 355 boring only in Patna & that’s also of govt.”
2. Then where should we get water from? According to 2018 report of Central water commission, India requirement of water is 3000 BCM (billion cubic meters) of water a year. Though irregularly but rain brings down 4000 BCM of water a year. Being among the most inefficient countries, we hardly capture 10-15% of rainwater, the rest of which flow into the salty sea with the lives of hundreds in it.
“As we know every year, in Mumbai there is around 7.1-inch rain per month. Whole Mumbai becomes an island in monsoon season still we didn’t have tried to make proper drainage system. A solution to this problem can help the water-deficit region of Maharashtra.”
3. People who have illegally occupied natural water catchment areas like ponds and lakes are now afraid of storing rain-water underground because they think water will wear out their foundations, what a tragedy.
DISCUSSION SIDELINE POINTS:
Many countries have started working on a solution for this. If we talk about China, China officially announced to construct FOREST CITY in Liuzhou. It is created to fight pollution.
We can start using greywater for the flush. RO system waste around 2/3 of water that can be used for dish or clothes washing.
Vacuum flush can be created so there will be less need for water at all for the flush.
IIT Gandhinagar has been saving nearly 3 lakh litre water per day. And it has been doing this since 2015. It’s because of the institute’s initiative to have a sustainable campus, a sewage treatment plant installed in 2015 allows it to use recycled water to maintain green cover on the campus. IIT-Gn has also developed a rainwater harvesting system for the purpose of conserving drinking water.
WRC Global Blockchain Hackathon was held in Maharashtra. This event Challenge participants to create an innovative application using blockchain, AI & IoT technologies to help solve the world’s growing water challenges. The participants had designed a program using IoT meter that first, they will analyse the data of polluted water produced by each industry. IoT meter will give an amount or rate of that polluted water. All data will store in blockchain so no one can change it. Now we will make an index of industries which produce most polluted water & how much they recycle it. Now they all be given a rank.
CONCLUSION:
Unlike shortage of fossil fuel like coal and petroleum, the water crisis doesn’t demand so much rigorous technical research for alternate solutions, rather we just lack efficient management of water resources.
People in India are so obsessed with development figures that basic needs have no significance to them. They may be a fan of their defense ministers but they even don’t know the name of their water minister.
We take proud of being a nuclear weapon state but the fact to be among the most inefficient nation in management of valuable resources like water and even air goes in one ear and comes out from another.
We extracted a lesson from thirsty crow story to be hard-working in life but we never thought why the crow threw pebbles instead of drilling a hole in that earthen pot.
India has to opt to be smart at water management by developing closed-loop system instead of age-old more demand – more supply approach. Enough attention must be given to behavioral change.
In the end, we will conclude by one simple equation:
Indian Water Crisis = Mismanagement + Ignorance + Climate Change.
Reading Time: 5minutesHere, I’m going to talk about about what is capture the flag and how can you get started with it.
Many of you will have an idea about childhood’s play CTF. In which we had few teams looking for their flag. CTF for cybersecurity is almost the same as the “on-field” one. The Ancient Romans used a board game version of CTF games to train their children in war strategy and battle formations. In 2007 the US Army created the US Scouting Service Project, which tackles hypothetical scouting missions in a sandboxed environment.
The penetration of Information technology to such depths in common life has resulted in great convenience and service but they also present their own glitches, the threat to be hacked by wicked hackers.
So let us begin the war to save the world from the cyber attacks.
There are two types of CTFs:
Attack-Defence
Jeopardy
Mixed
Let’s talk about all one by one.
1.Attack-Defence
As the name suggests, teams will attack other team’s system and also defend their own system. There are usually two rounds. In the first round, few teams will be an attacker and other teams will be the defender. In the second round, those teams will switch from attacker to defender or vice-versa. In the defender’s system, there are flags in the text file or picture or video or any other format, which the attacker teams have to find. The attacker’s team can use any hacking tools to compromise the other team’s system. But they must follow the rules to ensure that they are not taking advantage over the other team. At the same time, the defending teams can do anything to defend their machine while following the rules assigned for them. They are not allowed to disable any network connections or turn off the machines. If there is any rule violation, the team gets disqualified.
2.Jeopardy
In this type of competition, there are certain numbers of tasks or challenges the teams require to solve and get the flag. Sometimes there are chained challenges like you have to get the flag for the first challenge to move to the next one. The challenge can be related to Cryptography, Web Exploitation, Binary Exploitation(pwn), Forensic and Reversing. You have to use the techniques related to the above topics and find the flag. Let’s discuss what those topics are.
Cryptography:
It is a method of protecting information and communications through the use of codes so that only those for whom the information is intended can read and process it. In CTFs, they provide us any documents in a format like doc, pdf, etc. in which there will be an encrypted message. We simply have to decrypt it using crypto and get the flag or get the clue to move further in the challenge.
Web Exploitation:
Web exploitation is a very vast topic. In CTFs, they provide the link of the websites. We have to use some techniques to get the flag. We can check the source code, understand the logic behind how website response to our browser, can play with cookies, use several injections, etc. There are lots of methods to deal with the website and find vulnerability which actually leads us to the flag.
Binary Exploitation(PWN):
The objective of PWN challenges is for the player to acquire access to a target system without the system administrator’s permission. The targets can be personal computers, servers, websites, networking devices or applications. This type of challenge requires the knowledge of assembly language, how the compiler works also about networking.
Forensic:
This kind of challenges can include file format analysis, steganography, memory dump analysis, or network packet capture analysis. Any challenge to examine and process a hidden piece of information out of static data files (as opposed to executable programs or remote servers) could be considered a Forensics challenge. A real-world computer forensics task would hardly ever involve unraveling a scheme of cleverly encoded bytes, hidden data,files-within-files, or other such brain-teaser puzzles. One would typically not bust a criminal case by carefully reassembling a corrupted PNG file, revealing a photo of a QR code that decodes to a password for a zip archive.
Reverse Engineering:
Reverse Engineering is taking apart an object to see how it works in order to duplicate or enhance the object. The practice, taken from older industries, is now frequently used on computer hardware and software. In software reversing, we have to understand the code and write the code which performs the reverse task of the main code. This kind of challenges obviously requires a good knowledge of C, C++, Java and python language.
3.MIX
In mix type of challenges, there will be any combination of both types of challenges. Or there can be mainly attack-defense and jeopardy questions as a bonus.
So, there are lots of topics required for capture the flag.
You might be wondering…. Is it difficult?
The answer is unpredictable. Even in programming, if you know any computer language doesn’t mean you can solve competitive questions. Likewise knowing all the concepts doesn’t make you a hacker. You have to practice a lot. Here I will provide links from where you can learn or practice to capture the flag.
CTFtime: CTFtime is a site where you will find all the information regarding upcoming CTF challenges, the writeups, ranking of the teams across the globe.
picoCTF: It is a school-level competition but they keep the questions on the site for practice. This is the best site to start your journey in hacking.
Reading Time: 8minutesSince the past few days, there has been a buzz around everywhere, Not only in India but the world around. For some, it’s a challenge for others its pride. So, what’s it all about? You are right, for every Indian, it’s a moment of great pride and honour to launch our next moon mission Chandrayaan-2. But before discussing it, let us brush up our knowledge on the whole series of Indian Lunar Mission “THE CHANDRAYAAN PROGRAMME”.
Why Moon?
Since childhood we have been witnessing the white round moon ‘our chandamama’ grow big and small daily. Many of us had dreamt to go to the moon and play with the stars. But growing up we realise that the moon is not our neighbour next window but yes somewhere closer to our childhood. So, let’s fulfil our childhood dream and fasten our seatbelts to go to moooooooon!!!!!!
Being Earth’s only natural satellite moon provides the best linkage to Earth’s early history. It had witnessed each and every moment of our existence. It offers a great historical record of the inner Solar system environment. Though there are a few explained models, the origin of the Moon still needs further explanations. Extensive mapping of the lunar surface, to study variations in lunar surface composition is essential to trace back the origin and evolution of the Moon and this can further be helpful to study the origin and evolution of solar system and universe.
Chandrayaan programme is India’s Lunar Exploration Program. It is a series of outer space missions under the Indian Space Research Organisation (ISRO). The program consists of different parts which are a lunar orbiter, impactor, future lunar lander and rover spacecraft.
The Chandrayaan project was announced on 15 August 2003 by then Prime Minister Atal Bihari Vajpayee. This program was launched to boost Indian space programs and embarking India’s name in history.
Chandrayaan is a multi-phase mission-
The first phase includes the launch of CHANDRAYAAN – 1 which was a lunar orbiter.
The second phase includes the launch of soft lander/Rover Vikram and Pragyan as CHANDRAYAAN-2.
The third phase is planned to be an in-situ sampling collection expected in 2024 as CHANDRAYAAN-3.
CHANDRAYAAN-1
Launched on 22 October 2008 Chandrayaan 1 was the first milestone for Indian lunar programme. It was launched by ISRO from Satish Dhawan Space Centre, Sriharikota. It was unique in its sense that it was researched and developed fully in India by Indian scientists and researchers. The vehicle was inserted in the lunar orbit on 8 November 2008. On 14 November 2008, the Moon Impact Probe (MIP) separated from the Chandrayaan orbiter at 14:36 UTC and struck the south pole in a controlled manner, making India the fourth country in the world to place its flag on the Moon. The probe hit near the crater Shackleton at 15:01 UTC (20:31 IST). The location of impact of the probe was named as Jawahar Point.
The estimated cost of the project was around ₹386 crore (USD 56 million). Along with other objectives, the area around polar regions was of high interest as it may contain ice and may result in the discovery of water on the moon. The lunar mission in total carried 11 payloads, five of them were ISRO payloads and six payloads from other space agencies including NASA, ESA, and the Bulgarian Aerospace Agency. The payloads form these agencies were carried free of cost.
The stated objectives of this mission were: –
perform high-resolution remote sensing of the moon in – visible, near-infrared (NIR), low energy X-rays and high-energy X-ray regions
survey the lunar surface to produce a complete map of its chemical characteristics
prepare a three-dimensional atlas of both near and far side of the moon
conduct chemical and mineralogical mapping of the entire lunar surface for distribution of mineral and chemical elements such as Magnesium, Aluminium, Silicon, Calcium, Iron and Titanium and also high atomic number elements such as Radon, Uranium & Thorium.
test the impact of a sub-satellite (Moon Impact Probe – MIP) on the surface of the Moon as a forerunner for future soft-landing missions
The mission carried five scientific payloads from India, according to the ISRO these were:
Terrain Mapping Camera (TMC), which provided a high-resolution map of the moon.
Hyper Spectral Imager (HySI), which performed the mineralogical mapping.
Lunar Laser Ranging Instrument (LLRI), which returned information about the moon’s topography (height of certain features).
High Energy X-ray Spectrometer (HEX), which examined radioactive elements on the surface.
Moon Impact Probe (MIP), which was intentionally crashed into the moon’s south pole. Its impact helped Chandrayaan-1 in its search for lunar water.
What happened when: Timeline of Chandrayaan – 1
15th August 2003: Chandrayaan programme was announced by Prime Minister Atal Bihari Vajpayee
22nd October 2008: Chandrayaan-1 takes off from the Satish Dhawan Space Centre, Sriharikota
8th November 2008: Chandrayaan-1 enters the Lunar Transfer Trajectory
14th November 2008: The Moon Impact Probe ejects from Chandrayaan 1 and crashes near the lunar South Pole — confirms the presence of water molecules on Moon’s surface
28th August 2009: Chandrayaan-1 programme ends
What we Achieved from this mission?
1. Water on the Moon
On 18 Nov 2008, the Moon Impact Probe was released from Chandrayaan at a height of 100km. During its descent to the moon surface, Chandra’s Altitudinal Composition Explorer (CHACE) recorded evidence of water on the moon. This discovery was later confirmed by JPL-Brown University payload – Moon Mineralogy Mapper (M3), a payload by NASA. M3 detected spectral lines near the wavelengths in the range of 2.8 – 3.0 microns, a property attributed to water and Hydroxyl ions. It is believed that the formation of Hydroxyl ions and water molecules on the lunar surface is an ongoing process.
According to European Space Agency (ESA) scientists, the lunar regolith (a loose collection of irregular dust grains making up the Moon’s surface) absorbs hydrogen nuclei from solar winds. The hydrogen nuclei and oxygen present in the dust grains interact and are expected to produce hydroxyl (HO−) and water (H2O).
2. Imaging of North and South Pole of the Moon
This was done by two different devices namely –
Terrain Mapping Camera (TMC)
Hyper Spectral Images (HySI)
3. 3-D profile of Clavius (one of the largest craters on moon)
Lunar Laser Ranging Instrument (LLRI) mapped Clavius, the third largest crater on the near side of the moon, a feature observable with little aid and even with the naked eye.
The mineral content on the lunar surface was mapped with the Moon Mineralogy Mapper (M3), a NASA instrument on board of the orbiter. The Oriental Basin region of the Moon was mapped, and it indicates an abundance of iron-bearing minerals.
Chandrayaan-1 Imaging X-ray Spectrometer: The purple arrow shows the spacecraft track over the Moon; the different coloured rectangles show the area of the Moon that C1XS was looking at. The yellow and red areas show strong X-ray signals that correspond to Silicon, Aluminium and Magnesium, at the right hand end the green/turquoise area shows X-rays due to Calcium.
4. Mapping of various minerals
The mineral content on the lunar surface was mapped with the Moon Mineralogy Mapper (M3), a NASA instrument on board of the orbiter. The Oriental Basin region of the Moon was mapped, and it indicates an abundance of iron-bearing minerals.
Chandrayaan-1 Imaging X-ray Spectrometer: The purple arrow shows the spacecraft track over the Moon; the different coloured rectangles show the area of the Moon that C1XS was looking at. The yellow and red areas show strong X-ray signals that correspond to Silicon, Aluminium and Magnesium, at the right hand end the green/turquoise area shows X-rays due to Calcium.
5. Mapping of Apollo landing sites
In January 2009, ISRO announced the completion of the mapping of the Apollo Moon missions landing sites by the orbiter. Six of the mapped sites included landing sites of Apollo 12, 14 and 16 (can be referred in the previous image).
6. Radiation environment around the Moon
Radiation Dose Monitor or RADOM-7 (a payload from the Bulgarian Academy of Sciences) examined the radiation environment around the moon.
End of the mission
The mission was launched on 22 October 2008 and was expected to operate for two years. However, around 20:00 UTC (11:00 IST) on 28 August 2009 communication with the spacecraft was suddenly lost. Chandrayaan-1 made 3,400 orbits of the moon and continued transmitting data until 28 August 2009, when controllers permanently lost communication with the spacecraft. The probe had operated for 312 days. Earlier it was expected that the craft crashed into the lunar surface but in 2016 it was found still to be in the orbit. Although the mission lasted less than its expected duration, but a team of scientists from ISRO stated the mission to be successful as it had achieved 95% of its desired objectives in this time duration.
Chandrayaan 1 was a major success not only for Indian fraternity but also to Space Science as a whole. It expanded India’s footprint in space and proposed a whole together new dimensions to space. Chandrayaan-1 was lauded with a number of awards and recognitions as below –
The American Institute of Aeronautics and Astronautics (AIAA) has selected ISRO’s Chandrayaan-1 mission as one of the recipients of its annual AIAA SPACE 2009 awards.
The International Lunar Exploration Working Group awarded the Chandrayaan-1 team the International Co-operation Award in 2008.
US-based National Space Society awarded ISRO the 2009 Space Pioneer Award in the science and engineering category.
So, this was the first Lunar mission of India, tricolour for the first time fluttered on the moon’s surface. Stay tuned for the upcoming section on Chandrayaan-2, which will surely set new heights to the Indian Space Research and fill us with immense pride and honour.
Reading Time: 16minutesCan you imagine a day without electricity? In this modernized world, we are heavily dependent on machines which directly or indirectly rely on electric power either your mobile, laptop, cooling, lighting equipment, automobiles(electric), trains, metros, medical equipment etc. The system involving the process from the generation of electric power to transmission to distribution is termed as power system. The power system is the largest and most complex man-made physical system.
The power system is a system that deals with the generation, transmission, distribution and the consumption of electricity. Power generating stations are not always close to the load centres especially in case of hydro, nuclear, and tidal generating stations. Here comes the role of electric power transmission. The electric power is transmitted over HVDC/HVAC lines which is then received by substations of various load centres where distribution sector comes into play.
Also, all power plants can’t work throughout the year with same capacity due to many factors (like weather factors, fault, maintenance etc.), so they need power back up during that time from other generating stations. Due to all these factors, for an uninterrupted power supply, the power grids of different parts need to be interconnected.
The fault occurred at any of these units may result in severe damage to the system. The most common faults are short circuit and rare one is the open circuit fault. The fault may occur due to a number of factors that may be natural, physical, mechanical or chemical etc. The main factors for the fault are natural including winds, lightning strike, floods and many others which are not in our control so under such condition it becomes very important to have fast, effective and efficient protective devices.
The effects of faults can be very drastic, under severe condition it may result into blackouts, failure of the power grid. One can understand it by the effect of power cut off in hospitals, transportation, mining sites, industries, and other institutions solely dependent on electric power. If you are a regular reader of CEV blogs then probably you would have striken with one of the amazing blogs over the blackouts in India and Ukraine by Rahul Kumar.
The faults are mostly short circuit faults in both DC or AC transmission lines, 60-80% of which occurs due to natural factors like strong winds, cyclones, lightening etc. In India, most of the electric transmission occurs on high voltage 3 phase AC lines though we are moving towards HVDC lines for long distance transmission due to several advantages over ac transmission
low power loss (Rdc < Rac due to skin effect),
asynchronous mode of transmission (enables us to connect the power grids operating at different frequencies due to no frequency restriction unlike AC),
smaller towers and less copper requirements (2 wires are required while HVAC requires 3 wires),
easy power flow control (no capacitive or reactive drop) etc.,
The conclusion is that HVDC transmission is more economical as compared to HVAC but for small and medium distance transmission HVAC transmission systems are more economical because HVDC involves convertor at sending end and invertor at receiving end which increases the setup cost to manifolds. HVDC transmission is also possible just because of the invention of AC.
HVDC is a complement of AC, not a competitor.
Now, let us come back to the discussion over fault. It is clear that the protection from fault is of immense importance. As soon as the fault occurs it becomes very important to detect, locate and isolate the faulty system to protect the rest of the system. The very first step for the protection against fault is to locate and detect the type of fault. Previously we were having electrically and mechanically controlled devices which are slow and less efficient. Now we are having power electronic devices to sense the faults very fast (senses faults in milliseconds). Here comes the role of relays. A relay in simple language is a device which senses a disturbance in the power system based on the measurement of current, voltage phasors or various other criteria and sends signal to take suitable action. There are number of relays available but most widely used is distance relay whose functioning can be explained as follows-
Distance Relay- Distance relay observes the power system based on the calculation of apparent impedance using the synchronised voltage and current phasors measurements at the bus where relay is provided. They are fast, accurate, directional, can provide backup protection. Primarily they were used only for transmission line protection but now they are also used for generator backup, transformer protection etc.
There is a total of 10 short circuit faults which can be categorised as follows-
Symmetrical fault- It includes the 3 phase to ground fault and are called symmetrical because I and v remain balanced even after fault. They account for 8-10% of the total faults in power system
Asymmetrical faults- It includes – line to ground fault (A-G, B-G, C-G : 75-80%), line to line(A-B, B-C, C-A : 5-7%), line to line to ground (A-B-G, B-C-G, C-A-G: 10-12%) and are called asymmetrical as I and v are no longer balanced after fault.
Symmetrical Components– To analyse the faults, sequence components are used as the faulted system may or may not be balanced, so it is better to convert the 3-phase system into the 3 sets of 3 balanced phasors –
zero sequence components (all phasors have equal magnitude and are in phase) :
Va0 = Vb0 = Vc0
positive sequence components (all phasors have equal magnitude and are 120° displaced from each other in same sequence as the original phasor). If a = 1∠120° then,
Vb1 = a2 Va1 ; Vc1 = a Va1 ;
negative sequence components (all phasors have equal magnitude and are 120° displaced from each other in the opposite sequence of the original phasor)
Vb2 = aVa1 ; Vc2 = a2 Va1 ;
Such that:
Now the sequence component can be calculated as:-
Similar conversion can be done for the current phasors also.
Fault Analysis by impedance calculations-
Assumptions-
Fault impedance is zero, i.e., solid grounding of the fault.
Pre-fault currents are assumed to be zero as they are negligible in comparison to the high short circuit currents.
System is in balanced state before the occurrence of fault.
Consider a balanced 3 phase transmission line
3 phase fault (Phase fault protection)–
Ia+Ib+Ic=0
If the fault has occurred at x percent of total distance from the start as shown in figure –
Vabc = x Zabc Iabc [As Vn =0]
V012 = x diag(Z0, Z1, Z2) I012
Using I012 = T-1 Iabc and Ia+Ib+Ic=0,
I0=0, I1= Ia and I2 = 0
Or V0 = V2 =0 and V1 = xZ1I1 = xZ1Ia = Va
Thus,
Now, x can be determined as the ratio of apprent impedance seen by the relay to the positive sequence impedance of the line and thus, the fault can be loacated using the line current and voltage measurement.
Line to Line fault (Phase fault protection)–
Consider a transmission line with B-C fault at x percent of the total length as shown below-
Ic + Ib = 0, Ia =0 [Pre-fault current are zero]
ΔVa =Va = 0,
ΔVb =Vb = x(Zs-Zm)Ib =xZ1Ib ,
ΔVc =Vc = -x(Zs-Zm)Ib = -xZ1Ib = -Vb,
,
which is same as the above case, so these two faults can be located with the same set of equations.
Line to Ground fault (Ground fault protection)-
Consider a transmission line with A-G fault at x percent of the total length as shown below-
Using Ic =Ib =0 and I012 = T-1 Iabc
I0= Ia /3, I1=a*Ia /3 and I2 = a2*Ia/3
ΔVb = ΔVc = xZmIa
ΔVa =Va = xZsIa
Va = x(Zs – Zm + Zm)Ia
Va = x(Z1+ Zm)Ia
The above equation is used for locating the ground faults.
Line to Line to Ground fault (Ground fault protection)-
Consider a transmission line with B-C-G fault at x percent of the total length as shown below-
Ia=0, ΔVb =Vb, ΔVc =Vc
Using Ia =0 and I012 = T-1 Iabc
I0= (Ib + Ic)/3
So, the ground faults can be detected by the above equations.
Zone Setting –
This is how the distance realays work. But the assumption described above are not found in pracitcal scenerios and hence creates inacuracy in the meaurements. To avoid that, models needs to be modified accordingly.
Distance relays are used to provide both primary as well as the backup protection. Primary protection should be fast and accurate while the backup protection should work only if the primary protection fails. This is done by setting up the impedance zones for the relays. Generally, 3 zones are set-up, first being for the primary protection while the other two for the backup protection.
Zone 1 is set upto 80% of the primary line impedance. The complete primary line is not considered in the zone 1 because measurement instruments (CT,PT) are present near the buses which are prone to give errors in measurement of apparent impedance, thus making it difficult to locate the fault. In addition, the assumptions used in the equations for the relays are not valid in the practical cases.
Zone 2 covers the complete primary line impedance and 50% of shortest adjacent line impedance. This is done so as to overlapping of zone 2 of 2 different relays. For example, in example below if zone 2 of R1 covers more than 80% of the BE then it will overlap with the zone 2 of DE which may create undesirable competetion between them to send the trip signal.
Zone 3 covers the complete primary line impedance and 120% of longest adjacent line impedance.
For example- Consider a 5bus system as shown below-
Zone1= 80% of ZAB
Zone2= ZAB + 50% of ZBE
Zone3= ZAB + 120% of ZBD
Co-ordination time interval (CTI) –
When fault F3 occurs the primary relay R3 should get the first chance to trip the signal and if it fails then zone 2 of R1 and finally the zone 3 of some relay should come into play. This is a crucial consideration as the objective of the power system is to supply the maximum possible power to the consumers. To ensure this, zone setting is done along with providing a time delay called CTI. Zone 2 is provided with 1CTI while the zone 3 is provided with 2 CTI as explained in the following timing diagram-
This is all about how distance relays works and how the fault can be detected but the principle of working also involve a number of situations that may lead to mal-tripping of line. Maltripping occurs when the apparent impedance seen by relay enter into the sensitive zone of the relay in a non-fault condition and the relay interpret it as fault issuing trip signal. The mal-tripping events are mainly associated with the zone-3 as it is extended over very wide area to provide backup protection. This situation may cause drastic impact on power system especially under overloading codition. Under stressed conditions, when any such maltrip occurs this resluts in increase in load over the other lines as system will tend to draw power from the other path causing cascaded outage and blackout. The blackout occurred in 31 July, 2012 in India is initiated by distance relay zone-3 maltripping of Bina-Gwalior line.
Events causing maltripping are briefed as follows:
Infeed and outfeed effect-
This effect is now almost nullified by the advancement in technology and modification in the operation of distance relay. Consider a 4bus 3 source system as shown below-
If the fault occurs ‘F’, apparent impedance seen by relay R1 –
Va = IabZ1 + Ibc *xZ2
Va = IabZ1 +(Iab + Ied) *xZ2
The above equation clearly indicates that Zr is increased by-
due to infeed from generator 2. This may push the Zr to move outside the sensitive zone of the relay and hence decrease the dependability of the relay.
If the Generator G2 is replaced by a load then the direction of Ied will be reversed and thus Zr will decrease by-
Zr = Z1 + xZ2 – *xZ2
This pushes the impedance into the sensitive zone of the relay, and may detect fault even for the healthy system and hence decreases the security. This is highly undesirable as it may lead to casacaded outage and blackouts.
Load Encroachment –
Load encrochment or overloading is the major reason causing zone-3 maltripping. In the power system, energy is not stored so, the equivalence between the generation and consumption of power is must. The power consumption is not uniform throughout the day and it also varies depending on the weather conditions. In India, demand is at peak during day hours of summer due to heavy operation of coolers, ACs, fans and pumps for irrigation in the farms. In addition, many hydro power plants fails to supply power in summer due to deficiency of water. Under such cases, power system operate close to its stability limit and any contingency under such situation may result in maltripping, cascaded outage and the blackouts. One such example in front of us is the blackout of July, 2012 in India. India is energy efficient country but still the above mentioned condition may cause overloading and turn the system stressed. The depecndancy on electric power is increasing day by day over the world. Though the generation of power is increased at very appreciable rate yet the consumption rate is not perfectly matched. Consequently, in the near future, the probability of power system to work at its stability limit will increase and for ensuring the reliability and security of power system, preventing measures to avoid such cascaded outages must be introduced, some of which are discussed briefly later in this section:
Power flow on transmission line
Apparent impedance seen by the relay R is given by-
which means apparent impedance is directly proportional to the square of voltage magnitude and inversely proportional to the apparent power flow.
Under peak load conditions, power flow from the bus i towards bus j (P-jQ) will be very high and the increase in reactive power flow also decrease the voltage. The combined effect of these may cause the Zr to enter into sensitive zones of the relay causing maltriping which decreases the security of power system and may lead to voltage collapse, cascaded outage and blackouts.
To avoid the malfunctioning of the relays due to load encroachment, a number of methods are being described. Some of the methods proposed are:
For the loads power factor is high (R/X) while for the faults power factor is generally low due to high reactance of the line in comparision to the negligible resistance. Thus by blocking the high power factor region (shedded in the figure) of the zones we can prevent the malfunctioning of the relay due to load encroachment.
Relay Boundary Setting Adjustment- Malfunctioning of the relay can also be avoided by modifying the zones of relays based on the loading conditon and power system structure.
Voltage stability criteria can be chosen for identifying the fault and allowing the relay to function only under that condition else not.
System state indicator (SSI) can be used as a measure of power system condition and taking suitable action based on that.
And many other such techniques. But still we don’t have economical and completely effective method without any drawback.
The most practical and widely adopted methods are ‘c’ and ‘d’ which are based on the connection between voltage stability and load fluctuations.
Firstly, letus discuss about Volatage stability. It is ability of the power system to maintain steady voltage at all the buses, when subjected to a disturbance. Voltage instability may arise due to loss of load, tripping of transmission line, cascaded outages, loss of synchronism of the generator, mismatch between reactive power demand and supply, high inductive reactance of transmission line causing high voltage drop etc.
Based on the duration of distubance causing, instability it is classified into following categories-
Short- term or transient voltage instbility(1-10 sec)
Long- term voltage instability(1-60 minute)
i. Automatic corrective actions are taken as operator actions are difficult due to time constraints
Operator interventions are possible for larger time scale
ii. Mainly caused by rotor anle imbalance and loss of sysnchronism. It includes automatic voltage regulators, excitation systems, turbine and governor dynamics, induction motors, electronically operated loads and HVDC interconnections also fall in this category
Mainly caused due to large electrical distance between generator and load. The instability is caused due to high import of power from remote generating station to load, a sudden load build up, large distubance etc. Components operating in the long-term time frame are transformer tap changers, limiters, boilers etc.
iii. Steady state analysis (how stressed the system is, how close the system to point of instability) are useful
Suitable model of system needs to assumed and analysis needs to be done for the whole time frame of disturbance.
Now, for finding the relationship between the voltage stability and load encroachment, a 2-bus system analysed to see the effect of load (P-jQ) on the voltage stability.
The power transfers from bus 1 to 2 are given by-
Where E= E∠δ is the voltage at bus 1, V= V∠0 is the voltage at bus 2 and X is the reactance of the transmission line between the 2 buses.
The above equations are derived from power flow analysis.
Normalising the terms as v=V/E, p= PX/E2 and q= QX/E2,
p = vsinδ and q = vcosδ – v2
Eliminating δ from these two equations,
v4 +(2q-1) v2 + (p2 + q2) = 0
Now, based on the above equations power and voltage relationship can be discussed in the following way-
P-Q-V 3D curve:- For each (p, q) point, we are having 2 values of ‘v’, larger (stable) and smaller (unstable). The nose point where these two values are equal gives maximum power point and increase in power beyond this limit will result in voltage instability.
2. V-P Curve- The figure below depicts that maximum active power transfer limit increase and the rate of decay of voltage with ‘P’ decrease with increase in the power factor as shown below-
v1 ,v2 will exist only if v2 is real i.e.,
If k is the power factor then, k = q / p;
and thus the nose point power or
So, the maximum limit of the active power at specific power factor exists above which the system may fail to maintain the voltage stability.
3. Q-Vcurve:- Voltage stability is closely related with available reactive power reserve (Reactive power margin). The points where dq / dv = 0 are termed as critical points or the nose points and they represent minimum reactive power compensation for a particular value of active power. On the left of nose points dq / dv< 0 i.e., VQ sensitivity is negative in this region showing the unstable region of operation for a particular value of active power. Whereas on the right of nose points dq / dv > 0 i.e., VQ sensitivity is positive in this region showing the stable region of operation for a particular value of active power
p = vsinδ and q = vcosδ – v2 , thus,
The distance between operating point and nose point is known as reactive power margin and it determines reactive power compensation required for avoiding the voltage collapse. It is clear from the figure below that reactive power compensation increases with an increase in normalised active power which increases the sensitivity of voltage with reactive power. Greater the load, greater will be the slope of q-v curve in the right side, and weaker will be the bus.
From this discussion, it is clear that voltage stability decreases with the load encroachment. Thus it is justified that both the distance relay maloperation and voltage stability are related to load encroachment in a similar way. Utilising this relationship, VQ sensitivity can be used as criteria to define the weakness of the bus and thus for the load shedding. This property can be used for providing an adaptive load shedding scheme to avoid the distance relay maloperation.
Are we the only living things in the entire universe? The observable universe is about 90 billion light years in diameter. There are at least one hundred billion galaxies, each with one hundred to one thousand billion stars. Recently, we’ve learned that planets are very common too. And, there are probably trillions and trillions of habitable planets in the universe, that revolve in the Goldilocks zone of their own stars. Which means, there should be lots of opportunities for life to develop and exist. But where is it? Shouldn’t the universe be teaming with spaceships?
Even if there are alien civilizations in other galaxies, there’s no way we’ll ever know about them. Basically, everything outside our direct galactic neighborhood, so called “Local Group”, is pretty much out of our reach forever, because of the expansion of the universe. Even if we had really fast spaceships, it would literally take billions of years to reach these places, travelling through the emptiest areas in the universe. So, let’s focus on the Milky Way.
Milky Way
The Milky Way is our home galaxy. It consists of up to four hundred billion stars. That’s a lot of stars, roughly ten thousand for every grain of sand on earth. There are about twenty billion sun-like stars in the Milky Way, and estimates suggest that a fifth of them, have an earth sized planet in its habitable zone “i.e the Goldilocks zone”, the area with conditions that enable life to exist. If only zero point one percent of those planets harbor life, there would be one million planets with life in the milky way. But wait, there’s more. The Milky Way is about thirteen billion years old. In the beginning, it would not have been a good place for life, because things exploded a lot. But after one to two billion years, the first habitable planet was born. Earth is only four billion years old, so there have probably been trillions of chances for life to develop on other planets in the past. If only a single one of them had developed into an interstellar civilization, we would have handshakes by now.
What would such a civilization look like?
There are three categories.
A type one civilization would be able to access the whole energy available on its planet. we are currently around zero point seven three on the scale, and we should reach type one sometime in the next couple hundred years.
Type two would be a civilization capable of harnessing all of the energy of its home star. This would require some serious science fiction, but it is doable in principle. Concepts like the Dyson Sphere.
Dyson Sphere is a hypothetical megastructure surrounding the sun and effectively uses the energy of the sun to fulfill the energy requirements of the planet.
Dyson Sphere
3. Type three is a civilization that basically controls it’s whole galaxy and its energy. An alien race this advanced would probably be godlike to us.
If we were to build gen operation spaceships that could sustain a population for around one-thousand years, we could colonize the whole galaxy in two million years. Sounds like a long time, but remember, the milky way is huge.
So, if it takes a couple of million years to colonize the entire galaxy, and there are possibly millions, if not billions of planets that sustain life in the Milky Way, and these other life forms have had considerably more time than we’ve had, then, where are all the aliens?
This, is the Fermi Paradox, and nobody has an answer to it. But there are some possible answers.
Let’s talk about Filters,
A filter in this context represents a barrier that is really hard for life to overcome. They come in various degrees of scary.
One: There are Great Filters and we’ve passed them. Maybe it is way harder for complex life to develop then we think. The process, allowing life to begin, hasn’t yet been completely figured out, and the conditions required may be really complicated. Maybe in the past, the Universe was way more hostile, and only recently things have cooled down to make complex life possible.
This would also mean that we may be unique, or at least one of the first, if not the first civilization in the entire Universe.
Two: There are Great Filters and they are ahead of us. This one, would be really really bad. Maybe life on our level exists everywhere in the Universe but it gets destroyed when it reaches a certain point, a point that lies ahead of us.
For example, awesome future technology exists, but when activated, it destroys the planet.
The last words of every advanced civilization would be:
“This new device will solve all of our problems, once I push this button!”
If this is true, then we are closer to the end than the beginning of human existence.
Or, maybe there is an ancient type three civilization or type three civilization, that can destroy the earth for its resources, for example consider a bird, we humans destroy their home for resources like woods, we can also be like a helpless bird for a type three civilization.
Maybe there is something out there, that it would be better not to discover. There is no way for us to know.
One final thought: maybe we are alone. Right now, we have no evidence that there’s any life besides us. Nothing. The Universe appears to be empty and dead. No ones sending us messages, no one answering our calls. We may be completely alone, trapped on a tiny moist mud ball in an eternal Universe. If we let life on this planet die, perhaps there would be no life left in the Universe. Life would be gone, maybe forever. If this is the case, we just have to venture to the stars and become the first Type Three civilization, To keep the delicate flame of life existing, and to spread it until the universe breathes its final breath, and vanishes into oblivion.
The universe is too beautiful not to be experienced by someone.
