Data representation professor peter cheung department of eee, imperial college london floyd 2. Data representation theory revision notes computer science. Floatingpoint representation ieee numbers are stored using a kind of scientific notation. They are collected from a variety of sources chapter 1. Many programmers think that hexadecimal or hex 1 numbers represent absolute proof that god never intended anyone to work in assembly language. The data structure is a representation of the logical relationship existing between individual elements of data.
Bits 03 comprise the low order nibble, bits 47 form the high. The emphasis is not on the techniques to produce these representations, but on the question of whether or not the representation best represents the data. Data representation 42 output formatting this group of modules supplement builtin formatting functions like repr, and the % string formatting operator. Yet, lots of the time, the data represents numbers just consider integers, for now. It is important to give an equal amount of space to each leaf value by doing so, we can get a clear picture of any patterns in the data its almost likeabarchartonitssidebutitstillshowstherawobservations.
The problem with ascii is that it only allows you to represent a small number of characters 128 or 256 for extended ascii. Data and knowledge representation representation lecture. The data type, assumed to reside in processor, registers during the execution of an arithmetic instruction. Qualitative data analysis is a search for general statements about relationships among categories of data. Data is represented with the help of characters such as alphabets az, az, digits 09 or. Note that the encoding of a document is not the same as the font it uses. Cambridge international as level computer science 9608. Data representation in computer systems chapter 2 7 an international standard code for representing nonroman characters like asian, greek, and russian characters is unicode double words double words a double word is a group of 32 bits or 4 bytes or 2 words cs 2401 comp. In particular we will see how types enable and guide data representation. Data representation refers to the internal method used to represent various types of data stored on a computer. In floating point number representation, only mantissam and exponente are explicitly represented.
Org web experience team, please use our contact form. Elevation, as a continuous land field characteristic, is usually stored in a vector file for easier data management, but is more suitable to be represented by a raster data model. Note that subtraction becomes trivial when you have an easy way to find the additive inverse of a number. Chapter 4 binary data representation and binary arithmetic. So, any time we want to do io, were working with one character at a time, and the ascii representation of the character. Each digit is multiplied by an appropriate power of 10 depending on its position in the number. Note that this is not the only way to represent floating point numbers, it is just the ieee standard way of doing it. The interactives are excellent as teaching resources many of them are linked here, while the notes themselves make excellent revision resources particularly for gcse. Data representation is a major part of the softwarehardware interface. Data structures pdf notes ds notes pdf eduhub smartzworld. Cmps375 class notes chap02 page 3 20 by kuopao yang. Binary data representation and binary arithmetic 4. We first look at a traditional problem representing numbers in binary. The following table illustrates the use of frequency distributions with qualitative data.
Cmps375 class notes chap02 page 1 25 by kuopao yang chapter 2 data representation in computer systems 2. It is a messy, ambiguous, timeconsuming, creative, and fascinating process. Computer science 9608 unit 1 theory fundamentals 1. Form 3 computer studies chapter 1 data representation in a computer notes 2112. Number systems, base conversions, and computer data representation decimal and binary numbers when we write decimal base 10 numbers, we use a positional notation system. Paper 4 notes along with the syllabus content available for students to download and study. Types and programming languages frank pfenning lecture 9 tuesday, october 2, 2018 1 introduction in this lecture well see our type system in action. Data can be defined as a representation of facts, concepts, or instructions in a formalized manner, which should be suitable for communication, interpretation, or processing by human or electronic machine.
This section covers all aspects of data representation numbers, text, images, and instructions. It could be in convenient units of hours, minutes or seconds depending upon. In order to work with data, the data must be represented inside the computer. Binary arithmetic computer data data is stored as binary. The pie chart follows the principle that the angle of each of its sectors should be proportional to the frequency of the class that it represents.
In other words, a data structure defines a way of organizing all data items that consider not only the elements stored but also their relationship to each other. Purpose of unit 3 the aim of this unit is to look at a variety of ways to represent data and to compare these for the best representation of the data given. Data and knowledge representation representation lecture 3. It is also called statistical data or simply statistics. Chapter 4 binary data representation and binary arithmetic 4. The investigator must record the occurrence of a phenomenon over a specific time interval. A2 9608 computer science notes a level 9608 computer. This might be ok if you are living in an english speaking country, but what happens if you live in a country that uses a different character set. Data representation chapter one probably the biggest stumbling block most beginners encounter when attempting to learn assembly language is the common use of the binary and hexadecimal numbering systems. This product is the result of a lot of work done by my team over the past 6. How the data is actually represented in the computer hardware. Cmps375 class notes chap02 page 2 20 by kuopao yang. Data representation positional number systems positional.
Irwin reichstein may not be copied without permission page. Note that a byte also contains exactly two nibbles see figure 1. Sun technical notes this chapter contains technical notes on suns implementation of the external data representation xdr standard, a set of library routines that allow a c programmer to describe arbitrary data structures in a machinexindependent fashion. Karens pdf ascii table from a programmers view of computer architecture by goodman and. The data communication notes pdf data communication lecture notes book starts with the topics covering model of digital communication systems, pcm generation and reconstruction, introduction, ask,ask modulator, pulse shaping for optimum transmissions, information and entropy, conditional entropy and redundancy, matrix description of linear. Lecture notes on data structures using c revision 4. In other words, a data structure defines a way of organizing all data items that considers. Registers contain either data or control information control information is a bit or group of bits used to specify the sequence of command signals needed for data manipulation data are numbers and other binarycoded information that are operated on possible data types in registers. It is important to note that hexadecimal number provides a compact form or shorthand for representing binary bits. I am pleased to announce the launch of my new website oa computer science this product is the result of a lot of work done by my team over the past 6 or 8 months.
Form 3 computer studies chapter 1 data representation in a computer notes. The number of bits needed to store a piece of data increases with the amount of information. Data representation chapter one plantation productions. Graphical methods for presenting data a stem unit of one 10 and a leaf unit one 1.
Computer science is a science stream that involves several experiments and their planning. The computer has the ability to read in or print out a single character representation at a time. There are standards which define what the representation means so that across computers there will be consistancy. Lecture 1 intro to gis and gis vector and raster data models. There are three ways of representing negative fixed point binary numbers signed magnitude, signed 1s complement or signed 2s complement. Last time we talked about last time we talked about. Besides the tabular form, the data may also be presented in some graphic or diagrammatic form. Topics include binary, decimal, and hexadecimal numbers, and the conversions between them.
Form 3 computer studies chapter 1 data representation in. Graphical representation of data frequency polygon. It refers to the internal method used to represent various types of data stored on a computer. The ieee 754 standard defines several different precisions. A tutorial on data representation integers, floatingpoint numbers. Registers contain either data or control information. The geographers, economists, resource scientists and the decision makers use a lot of data these days. Knowledge representation tutorial to learn knowledge representation in data mining in simple, easy and step by step way with syntax, examples and notes.
In the data representation topic students will study the use of binary and hexadecimal number systems. Note that we have many different representations for any number. Number systems, base conversions, and computer data. For each data item, the marshalled string contains a. Without displaying the values for each observation taken from the population, it is possible to. Notes 35 data collection, processing and analysis geography pattern etc.
This includes their roles in computing systems, such as the use of hexadecimal in colour definitions such as in html and css. Data representation introduction to unit 3 in this unit you will look at different ways to represent data in tables, charts, graphs and diagrams. Perhaps, this is the simplest diagram that can be used to display data and that is the reason why it is quite limited in its presentation. Inf2c computer systems 20082009 2 lecture outline the bit atomic unit of data representing numbers representing text. To know data representation in computer we must know following number system. Negative numbers may be in a signed magnitude or signed complement representation. Work through the questions on the revision template focusing on weaker areas first. Data representations data representation initial notes by prof.
Tabulation orderly arrangement of data in rows and columns. The pprint module can print almost any python data structure in a nice, readable way well, as readable as it can make things, that is. How we interpret or conceptualize the internal representation. Data analysis is the process of bringing order, structure and meaning to the mass of collected data. Data representation 49 the marshal module this module is used to serialize data. Data representation data representation is defined as the methods used to represent information in computers. Frequency distribution tables can also be utilized for qualitative data. Here you can download the free data structures pdf notes ds notes pdf latest and old materials with multiple file links to download. Ncert class 11 computer science data representation in computers. The number system that you are familiar with, that you use every day, is the decimal number system, also commonly referred to as the base10 system. Covers topics like histograms, data visualization, preprocessing of the data etc. The sign of the integer is indicated by the leading bit. Presentation of data in statistics definition notes pdf. Data representation theory and quizzes for computer science gcse.
Data structure is a representation of logical relationship existing between individual elements of data. Computers use different types of numeric codes to represent various forms of data, such as text, number, graphics and sound. Many definitions are possible depending on context we will say that. Information and entropy, conditional entropy and redundancy, shannon fano coding, mutual information, information loss due to noise, source codings huffman code, variable length coding, source coding to increase average lnfomtation per bit, lossy source coding. Data representation the university of maine website. Given a base, b, distinct symbols must be used to represent the. From the meaning we can give some features of the term statistics or data below with example. Module 6 collection and presentation of data notes presentation and analysis of data in economics 30 making. Representation of data the data describe the properties of the phenomena they represent.
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