2014年9月22日星期一

Third week

                          22th ~ 26th

  • laws of arithmetic in logic and set operations
  • Process of solving problem

  This week, combining with the working on the Assignment 1, I gain a deeper understanding of implication, negation, conjunction, disjunction...several concepts and how to translate an implication from English languages to symbolic language and the reverse.
  The laws of arithmetic in logic and set operations is really cool, which teaches us to transform expressions of relationships between two statements like manipulating multiplication. By drawing Venn diagrams, we can prove them true.
  At Friday's lecture, Heap says no one in this University teach how to solve a problem systematically but he wants to teach us about it. He tells us to work as a team to investigate the changes of the pattern of little folds of a strip when being folded with the times increasing. It seems not very hard, but when we work on it with the solving steps that learned we find there are many things that worth thinking and learning.For example,What are the input and output of the question? To my mind, input is folding a strip and make it has several upward and downward folds.Output is to find the regularity or traits that can account for the results of every time's folding. Besides, when we write down every times pattern, how to make it more explicit for us to find regularity is very important.I choose to let '0'means upward and '1'means downward, which helps me to gain a comprehensive version of the problem in order to reduce the subtraction of distinguishing up and down signs. In addition, I make every sequences of figures to the middle alignment which can help to analysise the pattern from different sides. After trials and errors, I find the regularity. This exploration really teach me a lot. As Heap says, it is not the result but the process that makes you learn the most.



2014年9月15日星期一

Second week

                                           15th 

  • implication 
  • boolean function 
  Today, it begins with quantifiers with many exercises. It is a little bit confusing sometimes even Heap made a mistake.
  Then, we learn to use a boolean function to reveal a relationship between two sets which is more brief and familiar to python in other words computer than using mathematic symbols ∈ and ⊆ . 
  At last, Heap uses an order that his mom used to talk to him in his childhood" If you eat your vegetables, then you can have dessert" as a example to clarified that if the antecedent is false, then no matter the consequent is true or false the implication is always true. So, It is true that he could do not eat vegetables but to have dessert. This white-haired man is really cute , still looked like a innocent children. 
  This concept is a little bit difficult to understand. Heap does not make explanation because of time. I have been taught this concept in MAT137. The teacher says if the antecedent is false, there is no valid condition for us to show the consequent true or false which is called vacuous truth.I hope Heap could make a explanation in the next lecture because I hear many classmates talking about this after class.
                                   

                                     16th(Tutorial)

  • Meaning of "Some"

  The TA Madina is a cute girl, who leads us to review the knowledge of set learned in Lectures. Because of preparation of the tutorial material, I found it easy to follow Madina's words. 
  Although there is no new or hard something to learn, it answers a question that always bothers me.Before the tutorial, I always thought that "some" means "At least one but not all" and the fact is "Some" just means "at least" .Hence when drawing the Venn Diagrams, I always think about one more situation than others. 
  The question bothers not only me but some other students who raise the misunderstanding in the tutorial.  I guess it derives from my primary  English education. When I learn English words, I will awkwardly and directly translate English word into my mother language. "some" in Mandarin is the meaning of "At least one but not all". Luckily, the little but can not be ignored mistake has been eliminated now.


                                      17th

  • Implication, Conversee, Contrapositive
  • "Natural" Language(P => Q)

  At the beginning of the lecture, we do some exercise about 'Implication information'. I can understand the meaning of an implication if it is true, but I do not really understand the question"what can you deduce about the following sets". So the first half of the lecture, I am struggling to understand the answers from Heap and other students. 
  After the lecture, I asked one of my friends for help who is also not very sure the goal of the problem. Hence, I posted it on Piazza. To my delight, an instructor makes a quick reply. By the way, the instructor also eliminates my misunderstanding of a concept that the contrapositive of a implication that has quantifiers does not need to change the quantifier from the universal one to existential one.Here is the link of my post. 
  When it comes to the "Natural" Language part, Heap lists lots of sentences expressing implication P=>Q in English ways and asks us to found the corresponding P and Q. The first several sentences are plain and direct. We could find the answers without much thinking. 
  However, the next following ones become more and more confusing to distinguish which is the antecedent P and which should be the result Q. 
  I find a trick that what we need to do is to find what leads to what. For example, a sentence' You can't stay in enrolled in CSC165 without a pulse.'.We can re-read it in our mind in our own words such that 'Without a pulse means that You can't stay in enrolled in CSC165' or "With a pulse means that You can stay in enrolled in CSC165.'So the key condition that decides that whether you can enrolled in CSC165 is that if you have pulse. 
  Hence, obviously, we conclude that 'without a pulse' is the antecedent of the result "can't stay in rolled in CSC165". Namely, 'without a pulse'is P,'can't stay in rolled in CSC165' is Q. 
  I believes that my trick is like the steps of solving a problem as mentioned before and understanding the problem is an important key of solving a problem. 

   


First week of CSC165



                                1st Lecture

  • Goal of the course
  • Precision

  Honestly speaking, I was not very clear about what I am going to learn in CSC165. To my delight, the first lecture eliminate my doubts.
  At the first lecture, Heap showed the syllabus and some related notification.Then he explained "What's CSC165" and "Why CSC165", which motivated me to learn it well and determined to lay a solid foundation for my further Computer Science study.
  At the end of the lecture, he introduced the concept of precision of language to us,which he took some interesting English phrases(although some is difficult for a foreigner like me to understand) to show us the ambiguities in human language, which was difficult for computers to understand. Hence, the course will teach us to use rigorous mathematical expression and reasoning to convert our intentions to computers and keep a good balance of precision between computers and humans.




                           2nd Lecture and 3rd Lecture

  • Set and proposition
  • Steps to solve unknown problems

  Luckily,I took the MAT137 and CSC108. So, before Heap talking about set and quantifiers, I have reviewed set and proposition in MAT137. Besides, Heap uses the code of Python to demonstrate the concepts, I did not take much effort to understand it because the CSC108 was talking about Python.
  In addition,the four steps to solve a problem that we have not seen a template for was penetrating and useful for not only CSC165 but also many other subjects, like math and physics. As to myself, I believed the first step(Understand the problem) is most significant to solve a problem. When confronting with a seemed insolvable problem, I will learn to calm down and get to know what is given and what is required systematically instead of being confused by tons of figures and words. The last step(Review) is also very useful for thoroughly understanding roadblocks before and optimizing your solution by convincing a skeptical peer and leading you to extend the solution to another new problem.