I'm a student at the University of Nottingham studying an integrated masters in Computer Science. Since an early age, I've had an interest in technology, and my passion was ignited when I started making games when I was 11. I love helping people, and find it especially satisfying when I help someone to understand a problem they could not solve before.

In school, I was part of the Combined Cadet Force, and each week I taught new skills, such as first aid, to a group of up to 12 cadets at a time. I've also created a few apps for people all over the world (my first paid job was to create an online multiplayer game for an arm wrestling company, and I did this when I was doing my GCSEs).

I'm patient, friendly and passionate about computer science. If you don't understand something in the way I explain it first, I will always try to teach it in a different way so that you do understand it. Before each session, I'll ask you what you'd like to go over. I'll make the sessions as enjoyable as possible, which I believe is key to learning!

If you have any questions about me or would like to book a "Meet the Tutor Session", please don't hestitate to send me a message. Please include what exam board you're with and what you're stuck on. I look forward to meeting and helping you!

I'm a student at the University of Nottingham studying an integrated masters in Computer Science. Since an early age, I've had an interest in technology, and my passion was ignited when I started making games when I was 11. I love helping people, and find it especially satisfying when I help someone to understand a problem they could not solve before.

In school, I was part of the Combined Cadet Force, and each week I taught new skills, such as first aid, to a group of up to 12 cadets at a time. I've also created a few apps for people all over the world (my first paid job was to create an online multiplayer game for an arm wrestling company, and I did this when I was doing my GCSEs).

I'm patient, friendly and passionate about computer science. If you don't understand something in the way I explain it first, I will always try to teach it in a different way so that you do understand it. Before each session, I'll ask you what you'd like to go over. I'll make the sessions as enjoyable as possible, which I believe is key to learning!

If you have any questions about me or would like to book a "Meet the Tutor Session", please don't hestitate to send me a message. Please include what exam board you're with and what you're stuck on. I look forward to meeting and helping you!

No DBS Check

5from 1 customer review

Ed (Student)

April 14 2016

Thanks Henry!

The **sender's role is to add the parity bit**. ASCII characters are represented using a 7-bit binary string. A parity bit is added to the beginning of the binary string (i.e. at the most significant bit, or MSB). Since it's even parity, the **number of 1's** in the 8-bit binary string **must be even**.

For example, if the sender wanted to transmit the ASCII code for the letter 'A' (ASCII code 65), which is represented in binary as 1000001, a **0** would be added as the parity bit at the MSB. Therefore, **0**1000001 would be transmitted.

Similarly, for ASCII code 'C', which is represented in binary by 1000011, a **1** would need to be added to make the number of 1's even. In this case, **1**1000011 would be transmitted.

The **receiver's role is to check that the number of 1's in the received binary string is even**. If the binary string fails this parity check, the received will ask the sender to send the data agin.

For example, if 01000101 was received, this would fail the parity check; the number of 1’s in the binary string is not even, so the data would have to be resent. However, if 11000101 was received, then this would pass the parity check, meaning that it’s likely (though not necessarily guaranteed) that the data has been received as it was sent, and has not been corrupted.

The **sender's role is to add the parity bit**. ASCII characters are represented using a 7-bit binary string. A parity bit is added to the beginning of the binary string (i.e. at the most significant bit, or MSB). Since it's even parity, the **number of 1's** in the 8-bit binary string **must be even**.

For example, if the sender wanted to transmit the ASCII code for the letter 'A' (ASCII code 65), which is represented in binary as 1000001, a **0** would be added as the parity bit at the MSB. Therefore, **0**1000001 would be transmitted.

Similarly, for ASCII code 'C', which is represented in binary by 1000011, a **1** would need to be added to make the number of 1's even. In this case, **1**1000011 would be transmitted.

The **receiver's role is to check that the number of 1's in the received binary string is even**. If the binary string fails this parity check, the received will ask the sender to send the data agin.

For example, if 01000101 was received, this would fail the parity check; the number of 1’s in the binary string is not even, so the data would have to be resent. However, if 11000101 was received, then this would pass the parity check, meaning that it’s likely (though not necessarily guaranteed) that the data has been received as it was sent, and has not been corrupted.

An intractable problem is a problem that is solvable, but not in polynomial time or less. Such problems cannot be solved in time considered to be reasonable (i.e. not solvable quick enough to be 'useful').

An intractable problem is a problem that is solvable, but not in polynomial time or less. Such problems cannot be solved in time considered to be reasonable (i.e. not solvable quick enough to be 'useful').

Let's start by looking at the denary (i.e. base 10) number system. In base 10, you have a column for each digit in a number.

For example, with the number **5,867** you have a **5** in the **1,000'**s column, an **8** in the **100**'s column, a **6** in the **10**'s column, and a **7** in the **1**'s column. Essentially, this means: (5 x 1,000) + (8 x 100) + (6 x 10) + (7 x 1), which of course comes to 5,867.

The same principle can be used for hexadecimal to denary conversion. Hexadecimal uses the base 16 number system, so instead of have a column for 1's (10^{0}), 10's (10^{1}), 100's (10^{2}) etc. you have a column for **16 ^{0}**,

Hexadecimal uses numbers from 0-9 followed by A-F (i.e. 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F) to represent their denary equivalent 0-15. The letter **A** represents **10**, **B **represents **11**, and so on up to **F** which represents **15**.

So, for the hexadecimal value **A7**, we have a **7** in the **16**^{0 }column, and an **A** (which as we know represents **10**) in the **16 ^{1}** column. Therefore, to convert it to denary, we do:

A7 = (16^{1} x 10) + (16^{0} x 7)

= (16 x 10) + (1 x 7)

= (160) + (7)

= **167**

Therefore, the hexadecimal number **A7** is equal to the denary number **167**.

Let's start by looking at the denary (i.e. base 10) number system. In base 10, you have a column for each digit in a number.

For example, with the number **5,867** you have a **5** in the **1,000'**s column, an **8** in the **100**'s column, a **6** in the **10**'s column, and a **7** in the **1**'s column. Essentially, this means: (5 x 1,000) + (8 x 100) + (6 x 10) + (7 x 1), which of course comes to 5,867.

The same principle can be used for hexadecimal to denary conversion. Hexadecimal uses the base 16 number system, so instead of have a column for 1's (10^{0}), 10's (10^{1}), 100's (10^{2}) etc. you have a column for **16 ^{0}**,

Hexadecimal uses numbers from 0-9 followed by A-F (i.e. 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F) to represent their denary equivalent 0-15. The letter **A** represents **10**, **B **represents **11**, and so on up to **F** which represents **15**.

So, for the hexadecimal value **A7**, we have a **7** in the **16**^{0 }column, and an **A** (which as we know represents **10**) in the **16 ^{1}** column. Therefore, to convert it to denary, we do:

A7 = (16^{1} x 10) + (16^{0} x 7)

= (16 x 10) + (1 x 7)

= (160) + (7)

= **167**

Therefore, the hexadecimal number **A7** is equal to the denary number **167**.