#bison science

[bisonscience]

The Power of Binary

“There are 10 types of people in the world: those who understand binary and those who don’t.”

– The most overused binary joke in existence.

As I’ve mentioned in previous posts, computers use the binary system (base 2) to store data in the form of numerical values. Alone, a single bit, or binary digit, can only store two values. When combined, each additional bit adds a power of two, and therefore many additional values that can be represented. Though you may not think it at first, any decimal number (base 10) may be represented in binary.

Here’s a binary number. To convert it to decimal, use the following pattern with powers of two starting with the least significant digit (convert from right to left):

1001101

2^0 * 1 = 1

2^1 * 0 = 0

2^2 * 1 = 4

2^3 * 1 = 9

2^4 * 0 = 0

2^5 * 0 = 0

2^6 * 1 = 64

TOTAL = 78

To convert a decimal number to binary, divide the number by two. The remainder is the least significant digit. Continue the pattern using the result of the integer division until the quotient equals 0:

62

62 / 2 = 31 R0

31 / 2 = 15 R1

15 / 2 = 7 R1

7 / 2 = 3 R1

3 / 2 = 1 R1

1 / 2 = 0 R1

RESULT = 111110

An astute observer might say, “But what about negative numbers? I can have negatives in my Excel spreadsheet.” Well, Sherlock, there’s something out there called two’s compliment that resolves your conundrum; two’s compliment trades the most significant digit’s numeric representation ability for a flag to represent a negative number:

11111110

If you use the rules above, you may expect this value to be 254, but with two’s complement, it represents -2. Values that are assigned the two’s compliment property are known as signed integers, and those that use the additional bit for values are known as unsigned integers respectively.

For all of the aspiring programmers out there, here are the minimum and maximum values for each standardized data type, unsigned and signed:

Byte (8 bits): 0 to 255 / -128 to 127

Short (16 bits): 0 to 65,535 / -32,768 to 32,767

Integer (32 bits): 0 to 4,294,967,295 / -2,147,483,648 to 2,147,483,647

Long (64 bits): 0 to 18,446,744,073,709,551,615 / -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807

Also, people don’t actually code in binary. That would take about ~011110100001001000000 years.

Chase Garner ‘16

(image source: pcmerch.com)

[bisonscience]

The Magic of Passwords

It's been 120 days, and you know what that means! It's time to change your password.

Who doesn't love coming up with a new password? After all, using a minimum of three symbols and numbers and at least eight characters is very natural to us humans. We're so good a remembering passwords that most of us use only one of them for all of our authenticated services to avoid coming off as conceited.

But honestly, have you ever wondered how a simple text string can be used to protect all of your highly sensitive information?

When you sign up for a service, your chosen password is sent to a server and is properly salted and finely hashed. No joke! Salting is the process of adding a unique text extension to your password that only the server knows; this increases password security. Once the salt is appended, the password is run through a hashing algorithm, which guarantees a unique output for a unique input. Secure system do not store your password as text, only as a hash. When you login later, the server uses rehashes your password and checks it with the saved hash. If they match, you're in! (Some other cookie-based magic keeps you logged in, but I'll save that for another day.)

So what's all of the nonsense about "secure passwords?" The goal is a password that neither another human nor a computer could guess. Turns out, using a password that's at least eight characters with a number and a symbol is not the best way to go; computers are very good at guessing these types of passwords. No matter how complex "x75qr]J" looks to use humans, standard computers can now generate billions of random character combinations per second. If someone really wanted to brute force your short password, they could probably find a way to do it. Passwords like these are also a nightmare to remember.

The secret to a secure password is length. Something like "nyb*@mHvCxwH{hnZsaH:r6dJgJCF8yQsJ2P3dvVVHr]DR4qBHp" would be excellent, but the key to making your life better is a memorable phrase of your own creation (don't use well known phrases!). Let's say that your Uncle Bob is kind of sketchy. A password that you'd remember like, "UncleBobMakesMeUncomfortable" is much more secure than "X7qpl&31ac" because it is considerably longer. It's also better for you because you'll never forget that (unfortunately)! The more personal or clever the phrase, the better, and if you happen to include a number and a symbol or two, it will likely never be cracked by a computer. Ever.

A quick security tip: even if you have the world's best passwords, keep in mind that your stuff is only as secure as your electronics. If a friend has ever posted to your Facebook using your phone, you know what I mean.

Here's some password related fun for you. You've earned it!

Worst passwords: http://www.splashdata.com/press/PR121023.htm

Test your password’s security: https://howsecureismypassword.net

xkcd on passwords: http://xkcd.com/936/

Chase Garner '16

(image source: dduane.tumblr.com)

[bisonscience]

Announcement! 

It's been a little over a month since the launch of Bison Science, and we just wanted to say thank you to everyone who has supported the blog so far. We put in a lot of hard work this summer to get this thing rolling, and we're excited to see where it's going to go from here. In less than two weeks we'll be starting a new semester at Bucknell; with everyone back on campus, we hope to welcome some new writers and bring you even more content. But for the remainder of our summer vacation, Bison Science will be taking a short hiatus (so don't worry when you don't see any new posts in the next week - we'll be back!). And if there's something special you'd like to see on the blog this semester be sure to email us at [email protected] with suggestions! 

See you in the fall! 

[bisonscience]

Tips for surviving your freshman year as a science major

Being a science major is a lot of work. And your first semester will probably be the most difficult. Not only is the material tough; getting used to the way college courses are taught and what your professors expect of you makes studying a lot harder. Unfortunately, there is no magic formula for getting straight A’s. There are, however, some tried-and-true ways to make sure you are doing your best. They may be boring (and you’ll probably hear these over and over again) but they work. Here are our tips for how to best survive freshman year, science major or not:

Don’t be ashamed if you are struggling with the material.  This stuff is HARD. Everyone struggles with it at some point.

Take advantage of your resources.  Bucknell is great about providing help sessions, tutors, and facilitated study groups (sign up for these early!). Your professors will also have office hours, which can be tremendously helpful.

Figure out how and where you study best.  Some people study best when they are studying with a group, others prefer studying alone. Where to study? The library is a go-to choice, but some people prefer studying in their rooms (like Sophia), 7th street (where you’ll find Beth ... can you say bottomless coffee?) or an empty classroom.  The library is great because it has lots of options, from the quiet floors to group study rooms. And remember to leave distractions behind. If people are distracting you, move. If you’re constantly distracted by Facebook, try downloading a website blocking app such as SelfControl and blacklist it for a couple of hours.

Stay on top of your work.  We know they can be boring, but do the readings. It really helps to have an idea of what’s going on before you walk into lecture.  Read through your lab handout before lab. You’ll know what’s going on- and you’ll know which chemicals could burn your hands if you spill them and aren’t wearing gloves.  Five minutes of preparation before lab can save you hours of stress later.

Take good notes. And go over your old notes every once and a while to keep the material fresh in your memory. This makes studying for finals a lot less painful.

Don’t wait until the night before an exam to study (pretty basic, but needed to be said). We know it worked in high school, but in case you hadn’t noticed - this isn’t high school and that exam will kick your ass if you don’t take it seriously. And when you get your first bad exam grade (or what feels like a bad grade after acing high school), DON’T PANIC.  You can bring it back up, and even if you can’t bring it back up to perfection, a lower grade your first semester will not make-or-break you in the long run.

Stay on top of your work, take advantage of your resources, and get enough sleep, and you will be fine! Good luck!    

With love,

Bison Science