INF1339ComputationalThinking-Week2-Slides-Part2

Agenda Going over Answers for Week 2 Quiz Objectives Binary, Hexadecimal, Decimal Number Systems: ◦ Reminder ◦ Practical example (a fun activity!) Logic Circuits ◦ Reminder ◦ Practical example (a fun activity!) Next Week Participation Quiz (one minute paper) 3

Week 2 Quiz 2. (exact answer, number) Assume we have one row of an image that is represented by the following 32-bit pixel sequence: 11111100000000000011111111110000 Assume, also we are storing each “run” as an 8-bit byte. How many bits of memory are needed to store that image row using run-length encoding: 6

Week 2 Quiz 3. (multiple choice, one answer) If the information we wish to store is a coin toss, we require approximately 1 bit to store the two possible values. If the type of information we wish to store is the month of a year, we require 4 bits to store the twelve possible values. Suppose we want to store the possible letter grades available for graduate-level courses at the University of Toronto (A+, A, A-, B+, B, B-, FZ). How many bits do we need approximately? a) 2 b) 3 c) 4 d) 5 9

Week 2 Quiz 5. (multiple choice, one answer) How is the hexadecimal number (base 16) number, 53B represented in base 10? a) (5*16 0 ) + (3*16 1 ) + (11*16 2 ) b) (5*16 1 ) + (3*16 2 ) + (11*16 3 ) c) (5*16 2 ) + (3*16 1 ) + (11*16 0 ) d) (5*16 3 ) + (3*16 2 ) + (11*16 1 ) 12

Week 2 Quiz 6. (exact answer, text) What text is encoded in the following?(Hints: characters are represented by 8 bits and the encoding is given by the ASCII table) 0011001000101011001100110011110100110101 (don’t include any spaces in your answer). Exact answer: 2+3=5 15

(multiple choice, one answer) Given the following Donor Table, which SQL statement gives the names of donors between the ages of 30 and 45 years old who gave between $500 and $800 a) SELECT First, Last FROM Donor WHERE Age >=30 OR Age <=45 AND Amount >=800 OR Amount<=500; b) SELECT First, Last FROM Donor WHERE Age >=30 AND Age <=45 AND Amount >=800 OR Amount<=500; c) SELECT First, Last FROM Donor WHERE Age >=30 AND Age <=45 AND Amount <=800 AND Amount>=500 d) SELECT First, Last FROM Donor WHERE Age >=30 AND Age <=45 OR Amount >=800 AND Amount<=500; Week 2 Quiz 8. 18

Week 2 Quiz 9. (multiple choice, one answer) “(FLOOR=3 OR FLOOR=4) AND (NOT MOVING) AND BUTTON_PUSHED IMPLIES REAR_DOOR_OPENS” is an example of: a) An SQL statement b) A software requirement c) Some Python code d) A logic gate 21

Week 2 Quiz 10. (multiple choice, multiple answer) Which of the following statements are true about software requirements engineering? a) A software requirements document does not need to be precise. b) A software requirements document must be written so that both the client and software engineer can read and fully understand it c) Logic can be used to document software requirements d) Clients typically provide logic expressions to software engineers 22

Week 2 Quiz 10. (multiple choice, multiple answer) Which of the following statements are true about software requirements engineering? a) A software requirements document does not need to be precise. b) A software requirements document must be written so that both the client and software engineer can read and fully understand it c) Logic can be used to document software requirements d) Clients typically provide logic expressions to software engineers 23

Agenda Going over Answers for Week 2 Quiz Objectives Binary, Hexadecimal, Decimal Number Systems: ◦ Reminder ◦ Practical example (a fun activity!) Logic Circuits ◦ Reminder ◦ Practical example (a fun activity!) Next Week Participation Quiz (one minute paper) 24

Objectives Course Learning Objective 9 – students will gain experience in: 9. Sharing their knowledge and contribute to the learning of their classmates (Assessed through Class activities, Presentation, Individual Reflection) ◦ We all come with varied backgrounds in the course ◦ An important capability for information systems design professionals is to work with people who have different levels of technical expertise (“centre of the table” people) ◦ In this breakout, we will gain experience in this way by having students with technical backgrounds pair with those who do not during the exercises ◦ In addition, a great way to learn more about a concept is to help someone else learn that concept! To think more about and practice: ◦ Encoding data as bit strings within a computing system ◦ Logical values, logical operators, and circuits This Photo by Unknown Author is licensed under CC BY 25

Agenda Going over Answers for Week 2 Quiz Objectives Binary, Hexadecimal, Decimal Number Systems: ◦ Reminder ◦ Practical example (a fun activity!) Logic Circuits ◦ Reminder ◦ Practical example (a fun activity!) Next Week Participation Quiz (one minute paper) 26

Binary / Hexadecimal / Decimal: Reminder 27 From Riley & Hunt From https://www.ciscopress.com/articles/article.asp?p=3089352&seqNum=5

Converting Hexadecimal and Binary to Decimal 53B 16 = (5*16 2 ) + (3*16 1 ) + (11*16 0 ) = 1339 10 53B 16 = 0101 0011 1011 2 (binary) = (0*2 11 )+(1*2 10 )+(0*2 9 )+(1*2 8 )+(0*2 7 )+(0*2 6 )+(1*2 5 )+(1*2 4 )+(1*2 3 )+(0*2 2 )+(1*2 1 )+(1*2 0 ) = 0 + 1024 + 0 + 256 + 0 + 0 + 32 + 16 + 8 + 0 + 2 + 1 = 1339 10 2 8 2 7 2 6 2 5 2 4 2 3 2 2 2 1 2 0 256 128 64 32 16 8 4 2 1 16 8 16 7 16 6 16 5 16 4 16 3 16 2 16 1 16 0 4294967296 … … … 65536 4096 256 16 1 position 2 1 0 numeral 5 3 B

Converting Decimal to Hexadecimal Reminder 1. Divide the Decimal Number: Start with the decimal number you want to convert. 2. Divide by 16: Divide the decimal number by 16 and keep track of the quotient and remainder. The remainder will be the first digit of your hexadecimal number. 3. Repeat the Division: Divide the quotient from the previous step by 16 again. Record the new quotient and remainder. The remainder becomes the second digit of your hexadecimal number. 4. Continue Division: Keep dividing the quotient by 16, recording the remainders, until the quotient becomes 0. Each remainder becomes a digit in your hexadecimal number. 5. Convert Remainders to Hexadecimal Digits: Convert each remainder into its hexadecimal representation. Typically, 0-9 remain the same, and 10-15 are represented as A-F in hexadecimal. 6. Write the Hexadecimal Number: Write the hexadecimal digits in reverse order, from the last remainder you obtained to the first.

Converting Decimal to Hexadecimal Example (Reminder) 1. Divide the Decimal Number: Start with the decimal number you want to convert. 2. Divide by 16: Divide the decimal number by 16 and keep track of the quotient and remainder. The remainder will be the first digit of your hexadecimal number. 3. Repeat the Division: Divide the quotient from the previous step by 16 again. Record the new quotient and remainder. The remainder becomes the second digit of your hexadecimal number. 4. Continue Division: Keep dividing the quotient by 16, recording the remainders, until the quotient becomes 0. Each remainder becomes a digit in your hexadecimal number. 5. Convert Remainders to Hexadecimal Digits: Convert each remainder into its hexadecimal representation. Typically, 0-9 remain the same, and 10-15 are represented as A-F in hexadecimal. 6. Write the Hexadecimal Number: Write the hexadecimal digits in reverse order, from the last remainder you obtained to the first. 1. 1339 2. 1339/16 = 83 with remainder 11 3. 83/16 = 5 with remainder 3 4. 5/16 = 0 with remainder 5 5. In Hexadecimal: 11 is B, 3 is 3, and 5 is 5 6. 1339 in hexadecimal is 53B

Practical Example (a Fun Activity!) 31 https://www.ciscopress.com/articles/article.asp?p=3089352&seqNum=5

MAC (Physical Network) Address IPv4 addresses are represented using decimal (base 10) number system IPv6 addresses and Ethernet addresses are represented using hexadecimal (base 16) An Ethernet MAC address consists of a 48-bit binary value Hexadecimal is used to identify an Ethernet address because a single hexadecimal digit represents 4 binary bits. A 48-bit Ethernet MAC address can be expressed using only 12 hexadecimal values Since 1 byte equals 8 bits, a MAC address is 6 bytes in length. 32 https://www.ciscopress.com/articles/article.asp?p=3089352&seqNum=5

Other Fun Facts from the Cisco Article All MAC addresses must be unique to the Ethernet device or Ethernet interface To ensure uniqueness, every vendor that sells Ethernet devices must register with the IEEE to obtain a unique 6-digit hexadecimal (that is, 24-bit or 3-byte) code called an organizationally unique identifier (OUI) When a vendor assigns a MAC address to a device (a mobile phone, table, laptop, heater, fridge, etc.) or to an Ethernet interface, the vendor must do as follows: ◦ Use its assigned OUI as the first 6 hexadecimal digits ◦ Assign a unique value in the last 6 hexadecimal digits Example in the article: ◦ Cisco needs to assign a unique MAC address to a new device ◦ The IEEE has assigned Cisco the OUI 00-60-2F. ◦ Cisco would configure the device with a unique vendor code such as 3A-07-BC. ◦ Therefore, the Ethernet MAC address of that device would be 00-60-2F-3A-07-BC. 33

Individual Activity Conducted in Pairs If you have studied binary, hexadecimal in a past course, go to the left of the room If you have not studied binary, hexadecimal in a past course, go to the right of the room Pair one from left one from right (if uneven, no worries, just pair up) Meet someone new if possible! Help and support one another but do the activity individually 34 This Photo by Unknown Author is licensed under CC BY-SA

Individual Activity Conducted in Pairs Each person consider a device (phone, tablet, laptop) that you have with you in the room that is connected to the Wifi Activity 1: MAC Address: ◦ Figure out how to find the MAC, Physical, Ethernet, Wifi address (it may have different names) of your device (use a search engine or ChatGPT to figure out how to find it) ◦ Convert your hexadecimal MAC address to decimal and binary ◦ How many bytes would it take to store that address in decimal? Activity 2: IPV4 Address: ◦ Figure out how to find the IPV4 address of your Wifi connection ◦ Convert your decimal IPV4 address to hexadecimal ◦ How many bytes would it take to store that address in hexadecimal? 35

Agenda Going over Answers for Week 2 Quiz Objectives Binary, Hexadecimal, Decimal Number Systems: ◦ Reminder ◦ Practical example (a fun activity!) Logic Circuits ◦ Reminder ◦ Practical example (a fun activity!) Next Week Participation Quiz (one minute paper) 36

Logic Circuits: Reminder from the Lecture 37 Consider the following logic expressions and accompanying truth table: 1. (P OR Q) AND R 2. P OR (Q AND R) 3. NOT (P AND (Q OR R)) 4. (P IMPLIES Q) P Q R 1 (P OR Q) AND R 2 P OR (Q AND R) 3 NOT (P AND (Q OR R)) 4 (P IMPLIES Q) = NOT (P) OR Q 0 0 0 0 0 NOT (0) = 1 1 0 0 1 0 0 NOT (0) = 1 - 0 1 0 0 0 NOT (0) = 1 1 0 1 1 1 1 NOT (0) = 1 - 1 0 0 0 1 NOT (0) = 1 0 1 0 1 1 1 NOT (1) = 0 - 1 1 0 0 1 NOT (1) = 0 1 1 1 1 1 1 NOT (1) = 0 -

38 1. (P OR Q) AND R 2. P OR (Q AND R) 3. NOT (P AND (Q OR R)) 4. (P IMPLIES Q)

39 1. (P OR Q) AND R 2. P OR (Q AND R) 3. NOT (P AND (Q OR R)) 4. (P IMPLIES Q)

Example Logic Circuit Scenario : We are security system designers. Our task is to design a circuit for a vault. The vault has three input sensors: A, B, and C. 1. A - detects a retina scan. 2. B - detects a fingerprint scan. 3. C - detects a correct password entry. The vault should open (output 1 or “ON”) under any of the following conditions: 1. The retina scan (A) and fingerprint scan (B) are both successful. 2. The retina scan (A) is successful, and the password (C) is entered correctly. 3. The fingerprint scan (B) is successful, and the password (C) is entered correctly. However, the vault should NOT open (output 0 or “OFF”) if: 1. Only the retina scan (A) is successful. 2. Only the fingerprint scan (B) is successful. 3. Only the password (C) is entered correctly. 4. None of the scans are successful or no password is entered. 40

We can use a logic gate simulator or a paper and pen https://logic.ly/demo/ 41

Drag the 3 inputs on to the canvas: 1. A - detects a retina scan (ON = success). 2. B - detects a fingerprint scan (ON = success). 3. C - detects a correct password entry (ON = success). 42

Drag “Text” from “Other” (Scroll down) to label the three inputs: 1. A - retina scan 2. B - fingerprint scan 3. C - password 43

What gate(s) are needed for these conditions? The vault should open (output 1 or “ON”) under any of the following conditions: 1. The retina scan (A) and fingerprint scan (B) are both successful. 2. The retina scan (A) is successful, and the password (C) is entered correctly. 3. The fingerprint scan (B) is successful, and the password (C) is entered correctly. 44

What gate(s) are needed for these conditions? The vault should open (output 1 or “ON”) under any of the following conditions: 1. The retina scan (A) and fingerprint scan (B) are both successful. 2. The retina scan (A) is successful, and the password (C) is entered correctly. 3. The fingerprint scan (B) is successful, and the password (C) is entered correctly. A and B A and C B and C So, we need 3 AND gates 45

Drag three “AND” gates to the canvas and connect by clicking as indicated: • A and B • A and C • B and C 46

What gate(s) are needed for these conditions? The vault should open (output 1 or “ON”) under any of the following conditions: 1. The retina scan (A) and fingerprint scan (B) are both successful. 2. The retina scan (A) is successful, and the password (C) is entered correctly. 3. The fingerprint scan (B) is successful, and the password (C) is entered correctly. 1 OR 2 OR 3 So, the output of the AND gates should be an OR gate with three inputs (drag the OR gate and there is an option to set the number of inputs) The output of the OR gate indicates if the vault should open or not (I used a lightbulb output control!) 47

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Fingerprint scan okay and password correct  vault opens Only retina scan okay  vault does not open 49

Example Logic Circuit to Try Working in pairs or individually, using https://logic.ly/demo/ or paper / pen, create a logic circuit for the following: Scenario : You've been recruited by an intergalactic alliance to help design a security system for a spaceship. The spaceship has aliens from three different planets: Xanadu, Yarnia, and Zeltron. There are three input sensors for access to the spaceship's control room: A, B, and C. 1. A - detects if the alien is from Xanadu. 2. B - detects if the alien is from Yarnia. 3. C - detects if the alien is wearing a special Alliance Ring. The spaceship's control room should grant access (output 1 or "ON") under any of the following conditions: 1. The alien is from Xanadu (A) and is wearing the Alliance Ring (C). 2. The alien is from Yarnia (B) but doesn't need to wear the Alliance Ring (so, B alone is enough). 3. The alien is from Zeltron but MUST wear the Alliance Ring (C alone). However, access should be denied (output 0 or "OFF") if: 1. The alien is from Xanadu (A) without the Alliance Ring. 2. The alien is from Zeltron without the Alliance Ring (so, no input is detected). 50

Solution 1. For aliens from Xanadu with the Alliance Ring: A AND C 2. For aliens from Yarnia: B 3. For aliens from Zeltron with the Alliance Ring: C AND NOT A AND NOT B (This ensures that neither A nor B are active when C is.) Combining the conditions: (A AND C) OR B OR (C AND NOT A AND NOT B) 51

Agenda Going over Answers for Week 2 Quiz Overview and Objectives Binary, Hexadecimal Decimal Number Systems: ◦ Reminder ◦ Practical example (a fun activity!) Logic Circuits ◦ Reminder ◦ Practical example (a fun activity!) Next Week Participation Quiz (one minute paper) 52

Week 3 (Sept 25 and 27) Solving Problems Part 1 Next week will be in the main classroom for ~1.5 hours then move to breakout rooms for the last ~1.5 hours (find your breakout room on Quercus) Readings: ◦ Riley & Hunt, Chapter 4 “Solving Problems” ◦ Riley & Hunt, Chapter 5 “Algorithmic Thinking” ◦ Read about and choose possible problem to work on for the course Deliverables: ◦ In class participation assignment ◦ Weekly quiz due Monday at 2:30pm for Section 101 ◦ Weekly quiz due Wednesday at 5:30pm for Section 102 53

Agenda Going over Answers for Week 2 Quiz Overview and Objectives Binary, Hexadecimal Decimal Number Systems: ◦ Reminder ◦ Practical example (a fun activity!) Logic Circuits ◦ Reminder ◦ Practical example (a fun activity!) Next Week Participation Quiz (one minute paper) 54

One-Minute Paper (Participation) Quiz Quercus  Assignments  Week 2: Participation: one-minute-paper 55

Password: inf1339_riley&huntnewpw One-Minute Paper (Participation) Quiz 56