Computer Science - Final
Bridge (switch)
"smarter" device that has knowledge about the nodes located on each separate network
Fractional numbers
(12.34 or -0.001234) can be represented in binary by using signed-integer techniques
There _____ problems that do not have any algorithmic solution
*are*
Scientific notation
+-M x B^+-E (M is the mantissa, B is the exponent base (usually 2), and E is the exponent
Binary is a base __ positional numbering system
2
Binary operators require ____
2 operands
True color -? scheme and how many bits per color?
24-bit encoding scheme, 8 bits per color
The US ranked __ out of 39 developed countries in internet speeds
25
_____% of the time is spent on problem specification and program design
25-40%
In bit depth 1 byte can represent ____ levels and 2 bytes can represent _____ levels
256, 65,536
Megabyte
2^20
Gigabyte
2^30
Terabyte
2^40
/\
AND
Python 2 encoding is ____ and not all Python 2 internals support ______
ASCII, Unicode
SRAM
SRAM - does not need to be refreshed as long as power is applied
HDD vs. SSD - power comsuption
SSDs are more energy efficient, run cooler, and are quieter than HDDs
HDD vs. SSD - performance
SSDs have greater throughput and access time than HDDs
4G imposters and their theoretical download max speeds
HSPA: 56 Mbps - WiMax: 100 Mbps - LTE: 100 Mbps
Efficient distribution of resources
I/O controller - frees the processor to do useful work while the I/O operation is being completed *and* to ensure that a processor does not sit idle if there is useful work to do: operating system keeps a queue of programs that are ready to run
______ ______ has been adopted by industry leaders
Unicode standard
Python 3 and all built-in modules support ____ and the default encoding is _____, not ______
Unicode, UTF-8, ASCII
URL
Uniform Resource Locator
Explanation facility
allows the user to see the assertions and rules used in arriving at a conclusion
OAM advantage of assembly language
allows use of *symbolic addresses*
Internet protocol hierarchy
also called a protocol stack, has five layers
International ISP
also called tier-1 network or an internet backbone, provides global coverage
Alphabet for a given Turing Machine
always contains a special symbol b (for *"blank"*) - usually contains the symbols 0 and 1 and sometimes a limited number of other symbols
Common vector formats
adobe illustrator, corelDRAW, MathML
Advanced Encryption Standard (AES)
adopted for use by the U.S. government in 2001 - based on the Rijndael algorithm, block size is 128 bits, symmetric-key algorithm - three different ket-lengths: 128, 192, 256 bits
Database Management System (DBMS)
aids in data abstraction and program maintenance, aids in development of software that shares data, better control of security and access levels, reduction in data
Primitive operation
aka unambiguous operation
Vector graphics
all components of the image are stored, can be easily scaled without losing image quality
Bus topology
all nodes are connected to a single shared communication line
Analytic Engine
amazingly similar in design to a modern computer; expandable memory, arithmetic unit, logic processing capabilities (loops and conditional branching), and could use, as input, the results of preceding computations - but was NEVER actually built
Cryptographic Hash Function
an algorithm that is run on a file, producing a value called a checksum - changes in the file affect the checksum
Rapid prototyping
allows miscommunications between the user and the programmer to be identified and corrected early in the development process
Unicode
an international encoding standard for use with different languages and scripts - each letter, digit, or symbol is assigned a unique numeric value that applies across different platforms, programs and languages
Analog vs Digital representation
analog is curved - digital is straight line boxes
Gap test
analyze distance between zeroes
Poker test
analyze sequences of 5 numbers at a time, based on hands in poker
Boolean expression
any expression that evaluates to either true or false
Random access
any location in storage can be accessed at any moment in approximately the same amount of time, most semi-conductor memories and disk drives provide random access
Communication Protocol layers
application, transport, network, data link, and physical
First pass over source code
assembler looks at every instruction
Second pass
assembler translates source program into machine language
Code mapping
assigning each printable letter or symbol in our alphabet a unique number
Data compression algorithms
attempt to represent information in ways that preserve accuracy while using significantly less space
Rule-based system
attempts to mimic the human ability to engage pertinent facts and string them together in a logical fashion to reach some conclusion - must contain a knowledge base and an inference engine
Primary key
attribute or combination of attributes that uniquely identifies a tuple
Mobile speeds (2017)
average download speed: 22.69 Mbps (44th in world) - rural areas: 17.93 Mbps - average upload speed: 8.51 Mbps (65th in world)
Fixed speeds (2017)
average download speed: 64.17 Mbps (15th in world) - average upload speed: 22.79 Mbps (24th in world)
Cryptanalysis
breaking existing codes
Most computers come with ______ and new houses are wired for ___, ___, and ____
built-in Ethernet interface - phone, cable, and Ethernet
Internet Service Provider (ISP)
business whose purpose is to provide access from a private network to the internet, hierarchical, interconnecting to each other in multiple layers, or tiers, that provide ever-expanding geographic coverage
Linker
inserts requested object code from code libraries into the object code for the requesting program
Hash passwords
instead of storing passwords in plaintext, store a hash of the password, hashes are not reversible, so there is no way to determine the password that produced the hash, the consequences of a compromise are low
Primitives
instruction that computing agent understands and is capable of executing without further explanation
Prime number
integer greater than 1 that can only be written as the product of itself and 1
ASCII
international standard for representing textual information in the majority of computers - uses 8 bits to represent each character
John Napier
invented logarithms as a way to simplify difficult mathematical computations
Encryption and decryption
inverse operations
Encryption vs Decryption
inverse operations
In assembly language a symbol is defined when...
it appears in the label field of an instruction or data pseudo-op
Issues with using natural language
it can be extremely verbose, lack of structure makes it difficult to locate specific sections of the algorithm, it is too 'rich' in interpretation and meaning, not sufficiently precise
In order for the operation to be understandable...
it must also be doable (effectively computable) by the computing agent
Asymmetric encryption algorithm
key for encryption and decryption are quite different, but related
Foreign key
key from another table that refers to a specific key, usually the primary key
Integrated Development Environment
lets programmer perform a number of tasks within the shell of a single application program
O(n)
linear run-time
O(n) examples
linear runtime, sequential search
O(n log n)
linearithmic run-time
O(nlogn) examples
linearithmic, merge sort
Switch
located in a room called a wiring closet, contains a number of ports, with a wire leading from each port to an Ethernet interface
O(log n)
logarithmic run-time
O(logn) examples
logarithmic runtime, binary search (think phone book)
Rotating optical storage devices
longer access times than hard disk drives (CD, DVD)
Conditional and Iterative Operations
loop (the repetition of a block of instructions - while), continuation condition (determines if statement is true or false), infinite loop (continuation condition never becomes false)
Assembly Language (OAM)
low-level programming language, each symbolic assembly language instruction is translated into exactly one binary machine language instruction, *better than machine language*, machine specific
Low-level programming language exampls
machine language and assembly language
Computing agent
machine, robot, person, or thing carrying out the steps of the algorithm
Malware
malicious software
Time-sharing system
many programs can be stored in memory and allows programmer to enter system commands, programs, and data online
Multi-user operating system
many users can use a computer's resources simultaneously, must balance the requirements of the users, a problem with one user doesn't affect other users - i.e. Unix, mainframe operating systems
Sampling rate
measures how many times per second we sample the amplitude of the sound wave
Compression ratio
measures how much compression schemes reduce storage requirements of data
Amplitude
measures its loudness (unit are Electrical Voltage)
Scanning
measuring the intensity values of distinct points located at regular intervals across the image's surface
MAC
media access control
SSL (secure sockets layer)
method for achieving secure transfer of information on the Web
Biometrics
metrics related to human characteristics, more reliable in verifying identity than token and knowledge-based methods, can be used as a form of identification and access control
Secondary storage is expressed in ______
milliseconds
Interpretation
models can be used to recommend action or guide decision-making
Modem
modulates, or alters, a standard analog signal called a carrier so that it encodes binary information
High-level programming languages
more abstract than assembly language, user oriented, not machine specific (portable), use both natural language and mathematical notation in their design - these programs are translated into the appropriate machine instructions
RGB encoding scheme
most common format for storing color images, specify the red component, the green component, and the blue component separately
RSA
most common public key encryption algorithm, based on results from the field of mathematics known as number theory
Networking back in the day
most common way to transmit data was via switched, dial-up telephone lines
MP3
most popular and widely used digital audio format
Distributed environment
much of the computing was done remotely in the office, laboratory, classroom, and factory
MLT 40
multiply value in accumulator by the value in mem 40
Protocol
mutually agreed upon set of rules, conventions, and agreements for the efficient and orderly exchange of information
Primary storage is expressed in _______
nanosecond (fastest)
Pseudocode
natural language - used to express algorithms, a compromise between the 2 extremes of natural and formal languages, will not be unique, and similar to an outline of a program
Language schemes
natural language, formal language, pictorial, graphical
Composite primary key
needed to identify a tuple uniquely
Information sharing
network service benefit - a network is an excellent way to access scientific, medical, legal, and commercial data files
Resource sharing
network service benefit - ability to share physical and logical resources
Collaborative software (groupware)
network service benefit - facilitates the efforts of individuals connected by a network and working on a single shared project
Information utility (data warehouse)
network service benefit - nodes contain massive amounts of information that can be electronically searched for specific facts
Client-server computing
network service benefit - some nodes provide services, while the remaining nodes are users of those services
Electronic commerce (e-commerce)
network service benefit - use of computers and networking to support the paperless exchange of goods, information, and services
Interdisciplinary research
neurology, information theory, cybernetics
Single-user, single task operating system
no capability to distinguish between users, one user can effectively do one thing at a time - i.e. mobile phones
Stateless
no information about the exchange is permanently retained by the server
Lossless compression schemes
no information is lost in the compression, it is possible to exactly reproduce the original data
Binary storage devices
no practical universal storage medium exists, all forms of storage have drawbacks, computer systems contain several kinds of storage
Unsolvable problems consequences
no program can be written to decide whether any given program always stops eventually, no matter what the input, no program can be written to decide whether any two programs are equivalent, no program can be written to decide whether any given program run on any given input will ever produce some specific output
Internet Society
nonprofit, nongovernmental, professional society composed of more than 100 worldwide organizations
Secondary (storage hierarchy)
not directly accessible by the CPU, relatively cheap, non-volatile
Google Fiber
not widespread, download speeds of 200 Mbps, serving Atlanta, Austin, Charlotte, Kansas City, and Raleigh
Ciphertext-only attack
nothing is known about the corresponding plaintext
Bit depth or sampling precision
number of bits used to encode each sample
The user interface
operating system commands usually request access to hardware resources, software services, or information - to communicate with a user, a GUI supports visual aids and point-and-click operations
Deadlock prevention
operating system uses resource allocation algorithms that prevent deadlock from occurring in the first place (detect and recover from deadlocks)
Not all computers have ______
operating systems - simple computers that have limited capability
System security and protection
operating systems control access to the computer and its resources, safeguards password file, sometimes uses encryption to provide security
The Safe Use of Resources
operating systems prevent programs or users from attempting operations that cause the computer system to enter a "frozen" state *and* deadlock - each program is waiting for a resource to become available that will never become free
Arithmetic overflow
operation that produces an unsigned value greater than 65,535
E-business
orders are processed, credit is verified, transactions are completed, debits are issued, shipping is alerted, and inventory is reduced *all electronically*
Voice-oriented dial-up telephone network
originally a totally analog medium
Software development life cycle
overall sequence of steps needed to complete a large-scale software project
Stochastic components
parts of a system that display random behavior
Computer simulation
physical system is modeled as a set of mathematical equations and/or algorithmic procedures that capture the fundamental characteristics and behavior of a system
Spoofing
practice of impersonating a legitimate site for the purposed of stealing money or stealing identity
STA 0
print the result
Binding
process of associating a symbolic name with a physical memory address - OAM: symbolic name (label), memory address (line number)
Pass
process of examining and processing every assembly language instruction in the program, one instruction at a time
Social engineering
process of using people to get the information you want
Basic tasks of an operating system
processor management, memory management, device management, storage management, application interface, user interface
Procedural languages
program consists of sequences of statements that manipulate data items, random access memory stores and fetches values to and from memory cells
OAM source program
program written in assembly language
Disadvantages of assembly language
programmer must "manually" manage the movement of data items, programmer must take a microscopic view of a task, breaking it down into tiny subtasks at the level of what is going on in individual memory locations, *it is machine specific*
HTTP response message
returned from the server to the client along the same TCP connection
NOT operation
reverses, or complements, the value of a Boolean expression
3 Robot rules
robots cannot harm humans, robots must obey humans, subject to rule 1, and robots cannot injure humanity or cause harm through inaction
Three states of RTOS'
running (executing on the CPU), ready (ready to be executed), blocked (waiting for an event)
Infinite loop
runs forever
CD quality recording
sampling rate - 44,000 times per second, lower sampling rate produces distortions detectable to the human ear
Deliberative strategy
says that the robot must have an internal representation of its environment
I.e. - Credit card purchase online
security: transmit credit card number, authenticate: you are authorized to use the card, nonrepudiation: you really did order the item, integrity: you really did order that amount
HTTP request message
sent on the TCP connection from the client to the server, specifying the name of a web page
Operations used to construct algorithms
sequential operations, conditional operations, and iterative operations
Computer network
set of independent computer systems connected by telecommunication links
Why Use Networks?
share resources, communication, and interaction
Bulletin boards
shared public file where anyone can post messages and everyone is free to read the postings of others
Caesar cipher (shift cipher)
shifting each character in the message to another character some fixed distance farther along in the alphabet - encodes one character at a time
Plague Inc
simulation of infectious disease, pathogen infects "patient zero"
single most popular application of networks for the last 30 years
Cookie
small text file that web server sends to user's browser that gets stored on the user's hard drive
Intelligent agent
software technology designed to interact collaboratively with a user somewhat in the mode of a personal assistant - personalized web search engine
Middleware
software that allows separate, existing programs to communicate and work together seamlessly
Op code table
sorted list of all legal assembly language op codes and their binary equivalents
OAM object program
source program must be translated into a corresponding machine language program
Thesis
statement advanced for consideration and maintained by argument
Static or Dynamic
static models provide a snapshot at a single point in time (macroscopic view) - dynamic models: the model changes in response to input signals (the state variables change over time) & require more data to create and have limited generalizability
Stochastic or Deterministic
stochastic models use random number generators to model change or random events - deterministic models: no randomness is involved in the development of future states of the system & will always produce the same output from a given set of initial conditions
Types of Computer Models
stochastic/deterministic, static/dynamic, continuous/discrete
HLT
stop
Off-line storage
storage that can be physically removed or disconnected, increases general information security, useful for archiving data
STA 40
store value in mem 40
Models are an important way of _______
studying physical and social phenomena
Social networks
systems that create communities of users who share common interests
Hash function
takes password the user originally chooses, chops it up, and stirs it around according to a given formula (MD5 and SHA-1)
Solution path
takes us from the initial state to a winning configuration, and the graph nodes along the way represent the intermediate configurations
Conditional statements
the "question-asking" operations (if, then, else)
High-definition video conferencing
the 25/3 Mbps standard does not allow for a single stream of 1080p video conferencing, much less 4K video conferencing
Sequential algorithm
called the straight-line algorithm
Artificial neural networks
can be created by simulating individual neurons in hardware and connecting them in a massively parallel network of simple devices
Unambiguous operation
can be understood and carried out directly by the computing agent without further simplification or explanation
Two files are identical only if ...
the checksums generated from each file, using the same cryptographic hash function, are identical
Resolution of an image
the density of pixels used to represent the image
Data analytics
the discovery and communication of meaningful patterns in data, utilizes statistics, computer programming and operations research, used to describe, predict, and improve business performance
Metropolitan Wireless Local Access Network
turn a city into a wireless access zone, routers located throughout the region provide convenient, low-cost wireless internet access to all residents
Typical Operation
turn on computer - power on self test (POST): checks the CPU, memory, basic input-output systems (BIOS) for errors and activate hard disk drive: runs the first piece of the operating system: the bootstrap loader
Language services (assemblers, compilers, and interpreters)
type of system software - allow you to write programs in a high level
Input/Output systems
type of system software - allows you to easily and efficiently use the input and output devices that exist on a computer system
Operating system
type of system software - communicates with users, determines what they want, activates other system programs, applications packages, or user programs to carry out their request
Memory managers
type of system software - distributes memory space for programs and data
Information managers
type of system software - handle the organization, storage, and retrieval of information on mass storage devices
Scheduler
type of system software - keeps a list of programs ready to run on the processor and selects the one that will execute next
Utilities
type of system software - library routines that provide useful services either to a user or to other system routines
User interface
type of system software - provides user with an intuitive visual overview
Single-user, multi-tasking operating system
typical operating system on desktop and laptop computers - Microsoft's Windows and Apple's MacOS
Denial-of-service (DOS) attack
typically directed at a business or government web site - automatically directs browsers on many machines to a single URL at roughly the same time
Behavioral characteristics
typing rhythm, gait, voice writing style (sentence structure and use of prepositional phrases)
BMP (windows bitmap)
uncompressed, large, lossless, simple structure
Most WANs ...
use a store-and-forward, packet-switched technology to deliver messages - the intermediate station verifies the integrity of the message before forwarding it
Wi-Fi
used to connect a computer to the Internet when it is within range of a wireless base station
Real-time Operating Systems (RTOS)
used to control machinery, scientific instruments, industrial systems, very little user-interface capability, no end-user utilities, have advanced algorithms for scheduling
System commands
used to translate, load, and run programs
Algorithm
well-ordered collection of unambiguous and effectively computable operations that, when executed, produces a result and halts in a finite amount of time
Multimedia user interfaces
will interact with users and solicit requests in a variety of ways
Frequency test
with uniformity, expect roughly the same number of digits
Run-Time Analysis
worst or average case
Parallel processing operating systems
can efficiently manage computer systems containing tens, hundreds, or even thousands of processors
Neural network
can learn from experience by modifying the weights on its connections, can be given an initial set of weights and thresholds that is simply a first guess - network is then presented by *training data*
Site map or navigation bar
can provide a high-level overview of your site architecture
Worm
can send copies of itself to other nodes on a computer network without having to be carried by an infected host file
Model
capture the essence of the real thing, probably differ in scale from the real thing, omit some of the details of the real thing, lack the full functionality of the real thing
Attribute
category of information
Neuron
cell capable of receiving stimuli, in the form of electrochemical signals, from other neurons through its many dendrites - can send stimuli to other neurons through its single axon
First major decision (moving to e-commerce)
choose between in-house development and outsourcing
Library
collection of useful algorithms
Augmented Reality Applications
commerce, education, entertainment, gaming, medical, military, navigation, sports
Virus
computer program that infects a host computer and then spreads
Trojan horse
computer program that, unbeknownst to the user, contains code that performs malicious attacks
Wireless wide area access network
computer transmits messages to a remote base station provided by a telecommunications company
Scientific visualization
concerned with data extraction and data manimulation
Computer graphics
concerned with the technical issues involved in information display
Control operations
conditional and iterative - allow us to alter the normal sequential flow of control in an algorithm
Wide area network (WAN)
connects devices that are not in close proximity but rather are across town, across the country, or across the ocean - collection of machines (routers) with point-to-point connections - each router receives packets, decides where they go, and forwards them appropiately
Local area network (LAN)
connects hardware devices such as computers, printers, and storage devices that are all in close proximity
Ring topology
connects the network nodes in a circular fashion
Alan Turing
considered to be the father of theoretical computer science, devised techniques for breaking German ciphers, defined a standard for a machine to be called "intelligent" (the Turing Test), and wrote a chess program
O(1)
constant run-time
O(1) examples
constant run-time, add/sub/multiplication/division/comparison module
Gottfried Leibnitz
constructed a mechanical calculator called Leibnitz's Wheel - developed formal logic using a binary numeral system
Municipal WiFi
construction is a significant part of lifetime cost, financing is shared by both a private firm and the municipal government, paid for through taxes, nodes must be within range of each other, and need power - often installed on power and light utility poles
Posttest loop
continuation condition is test at the end of the loop body
Pretest loop
continuation condition is tested at the beginning of each pass through the loop
Tasks performed by OAM assembler
convert symbolic op codes to binary, convert symbolic addresses to binary, perform the assembler services requested by the pseudo-ops, put the translated instructions into a file for future use
Compiler
converts high-level language instructions into machine language instructions
Zero knowledge protocol
convince the recipient that the sender is who they claim to be without transmitting any real information
When data is passed between different encodings, the data runs the risk of _______
corruption
Summary of assembly language
creates a more productive, user-oriented environment than machine language
Raster graphics
each pixel is encoded as an unsigned binary value representing its gray scale intensity, individual pixels can be edited, # of bits used for each pixel affects image quality and amount of memory needed to store the image
Query languages
enable user or another application program to query the database, in order to retrieve information
Black and white representation
encoded with either a 0 (white) or 1 (black)
DES (data encryption standard)
encryption algorithm developed by IBM in the 1970s for the U.S. National Bureau of Standards - a block cipher that is 64 bits long
Verify file integrity
ensure the file has not been tampered with or corrupted during transmission, website publishes the hash values of its download bundles, so users can verify the file integrity, if hashes being compared differ in any way, the data being digested is not the same
Scientific methon
entails observing the behavior of a system and formulating a hypothesis that tries to explain its behavior
Design philosophies of RTOS
event driven: switches tasks when an event of higher priority needs servicing - time sharing: switches tasks on a regular schedule
Back propagation algorithm
eventually causes the network to settle into a stable state where it can correctly respond to all inputs in the training set
DES algorithm
every substitution, reduction, expansion, and permutation is determined by a well-known set of tables
\/
exclusive OR
Why construct a simulation model?
existence, physical realization, safety, speed of construction, time scale, ethical behavior, ease of modification
O(2^n) examples
exponential
Two types of information representation
external and internal
O(n!)
factorial
Factors to energy use
fan usage (heat), shut down during inactivity, power to operate
E-commerce
financial transactions are conducted by electronic means
Statistical model
find an analytical solution to a problem and predict behavior given a set of parameters and initial conditions, generated by fitting data collected, tested by collecting more data, or through simulation
Physiological characteristics
fingerprints, palm veins and palm print, DNA, iris recognition, retina, odor/scent
Application layer
firefox, internet explorer, safari - rules for implementing end-user services provided by a network, URLs, HTTP request and response messages
TLS (transport layer security) protocol
first defined in 1999, based on SSL and is nearly identical to SSL, nonproprietary, supported by the internet engineering task force
Normalize the number
first significant digit is immediately to the right of the binary point
UTF-32
fixed with byte representation - 4 bytes per code point
Theorem
ideas that can be proved in a formal and mathematical way
Church-Turing Thesis
if there exists an algorithm to do a symbol manipulation task, then there exists a Turing machine to do that task
Importance of formal algorithms in computer science?
if we can specify an algorithm to solve a problem, then we can automate its solution
Conditional statement examples
if-else statements
Decision tree for a search algorithm
illustrates the possible next choices of items to search if the current item is not the target - is linear
CRM (customer relationship management) strategy
improve customer satisfaction, build customer relationships, bring people back to your web site time and time again
Turing Machine
includes a (conceptual) tape that extends infinitely in both directions - can execute a whole sequence of instructions, can accept input, can store information in and retrieve it from memory, can take actions according to algorithm instructions, and can produce output
Router
individual networks are interconnected via a device called a ...
Packet
information block with a fixed maximum size that is transmitted through the network as a single unit
File addressable (addressability)
information is divided into files of variable length, files are selected with directory and file names, secondary, tertiary and off-line storage
AlphaGo Zero
initially programmed with the basic rules of GO - AlphaGo Zero is entirely self-taught
HDD vs. SSD - size and weight
HDD - 750 grams, SSD - 77 grams
States with free WiFi service at welcome centers and roadside rest areas
Iowa and Massachusetts
Fiber Optics
1 Gbps
HDD vs. SSD - price
1 TB HDD - $49-65, 250 GB SSD - $90-110
Unary operators require ____
1 operand
Broadband access
19.4% of US households don't have access to broadband based on 2015 threshold levels, in 2017 the US ranked 44th in the world for mobile download speed and 65th in the world for mobile upload speed
Initial implementation of the program may occupy only _____% of the total time
10-20%
Three different key-lengths
128, 192, and 256 bits - the key size specifies the number of repetitions used to convert the plaintext into the ciphertext
Color images
16 colors (4 bits per pixel), 256 colors (8bits per pixel)
_____% is spent on tasks that follow implementation
40-65%
Grayscale
8 bits can be used to represent 256 different shades of gray (0 black to 255 white)
TIFF - ___ or ___ bits per color, compressions can be ___ or _______
8 or 16, lossy or lossless
JPEG - ____ bit grayscale, _____ bit color, compression is ____
8, 24, lossy
GIF - ___ bit color palette, LZW ____ compression, is now _____
8, lossless, patent-free
iMessage encryption
Apple claims that iMessages are protected by end-to-end encryption (impossible for Apple or anyone else to descramble the messages)
Cities in Europe with Muni WiFi
Brussels, Dublin, Geneva, Helsinki, Liverpool, Milan, Paris, Venice
Cities in the US with Muni WiFi
Burlington, Cambridge, Charleston, Chattanooga, Cleveland, Denver, Houston, Honolulu, Indianapolis
DRAM
DRAM - requires stored information to be periodically re-read and re-written (refresh) or it will be lost
______ _______ are used to assign a number for each letter or character
Encoding systems
Natural language examples
English, Spanish, etc
Broadband Comparison
Europe: no data caps, upload and download speeds are 100 Mbps, cost i $60 for Tv, phone, and internet -- US: data caps (mediacom is 400 GB/month, comcast is 300 GB/month, AT&T is 150/250 GB/month), download speeds promised are 6-60 Mbps, download speeds delivered are 1-40 Mbps, and cost is $60/month for just internet
OAM language code
LDA, STA, MLT, ADD, STA, HLT
HDD vs. SSD - durability
NAND flash mounted to circuit means SSDs have better shock resistance than HDDs
~
NOT
Fastest to Slowest
O(1), O(logn), O(n), O(nlogn), O(n^2), O(2^n), O(n!)
Conditional Execution
O(if {condition} then {sequence 1} else {sequence 2}) = Max (O(condition), O(sequence 1), O(sequence 2))
Iterative Execution
O(loop(k) {sequence}) = O(k * sequence)
Direct Sequencing
O({a, b, c}) = max(O(a), O(b), O(c))
Ⓧ
OR
OAM design decisions
Op codes and include/exclude specific functions
Carrier rank
T-Mobile, Verizon, AT&T, Sprint
Transport layer
TCP, UDP - assigns port numbers to programs, remembers which program goes with which port
Compound Statements: (P /\ Q) \/ (~ P → Q)
Suppose P is true and Q is false - The compound statement is True
TCP
Transmission Control Protocol - the computer sending the data connects directly to the computer it is sending the data to, and stays connected for the duration of the transfer - computers guarantee that the data has arrived safely and correctly - quick and reliable, but computer has to monitor the connection and data - analogous to a phone call "back in the day"
Characters are assigned a number written in the form ______ - called a code point
U+XXX (ie. U+0041), the numbers are hexadecimal
Flash memory
USB flash drives, SD cards
UDP
User Datagram Protocol - the computer sending the data packages the information into little packets and releases them into the network with the hopes that they will get to the right place - relies on the devices in between the sending and receiving computers to get the data to where it is supposed to go - there is no guarantee that the data will arrive safely and correctly - very low overhead and similar to US Postal Service
Ten-gigabit Ethernet standard
Version of Ethernet with data rate of 10 billion bits per second, adopted by IEEE in 2003, commercial settings
Non-volatile memory
retain stored information without power, suitable for long-term storage
Well-known operating systems
Windows, Macintosh, Unix
Fastest ISPs by region
X-Finity (west and north east): 74 Mbps - Mediacom (Mid West): 57 Mbps - Suddenlink (south): 74 Mbps
Digitally sign documents
a document is used to generate a hash value, the user encrypts the hash of the document with their private key, producing a digital signature, to validate a signature - reverse the process
Digest
a hash is a digest, compile data into a small digest, one way operation, same size regardless of the data file size
Augmented/Mixed Reality
a live direct or indirect view of physical, real-world environment whose elements are augmented - real time
Turing's theory of computation
a machine, by shuffling symbols could simulate any conceivable act of mathematical deduction
Virtual Reality
a computer-simulated environment that can simulate physical presence in places in the real world or imagined worlds
Bootstrap Loader
a pure binary program, stored in a single 512 byte sector, impossible to create an OS without it, the very first program of your OS that is loaded directly by the BIOS and executed directly by the processor, loads the operating system into memory - allows it to begin operation and sets up driver programs that interface with and control hardware subsystems
Quantis
a random number generator exploiting quantum physics
Random behavior
a random sequence has no regular pattern or is unpredictable (ideal dice roll, digits of pi)
Checksum
a type of signature for a stream of data
Mediated reality
a view of reality is modified by a computer
Shared media technology
a wire is strung around and through a building, users tap into the cable at its nearest point using a transceiver, needs a protocol to govern access
Computing agent should be able to:
accept input, store information in and retrieve it from memory, take actions according to algorithm instructions, produce output
Sequential access
accessing pieces of information is in a serial order, one after the other, the time to access a particular piece of information depends on which piece of information was last accessed
Issues in modeling
achieving proper balance between accuracy and complexity
Summary of system software
acts as an intermediary between the users and the hardware
AES (advanced encryption standard)
adapted for use by U.S. government in 2001 - block size 128, symmetric key algorithm
ADD 40
add value in mem 40 to value in accumulator
Characteristics of knowledge representation scheme
adequacy, efficiency, extendability
Motivation to decrease standards
adherence to the higher standard was slow, wide swaths of the country have "good enough" broadband access if they are covered only by wireless carriers offering slower speeds than by cable or fiber ISPs, policy problem regarding internet access is solved
A model of an algorithm
be a well-ordered collection, consist of unambiguous and effectively computable operations, halt in a finite amount of time, produce a result
Backward chaining
begins with a proposed conclusion and tries to match it with the "then" clauses of rules
Forward chaining
begins with assertions and tries to match those assertions to the "if" clauses of rules
Hexadecimal Numbering System (base 16)
binary to base 16 (group in fours), base ten-binary-base 16 and other way
Octal Numbering System (base 8)
binary to base 8 (group in threes), base ten-binary-base eight and other way
Primary purpose of a operating system
to create a workable operating environment for the user
Location-addressable (addressability)
each individually accessible unit of information in storage is selected with its numerical memory address, primary storage, efficient
After raising the standard
data rates have increased markedly, the US move dup to be ranked 10th in the world for broadband internet, but it depends on which state you live in
SQL
declarative language that specifies combination of the built-in relational operators- based on relational algebra (procedural language) - SELECT, FROM, WHERE
2 strategies characterize robotics research
deliberative and reactive
Data analysis
descriptive and predictive models are generated from data collected
Virtual Reality Issues
desensitization, cyber-addiction, virtual criminality, virtual punishment
Blaise Pascal
designed and built one of the first mechanical calculators (Pascaline)
Difference Engine
designed to do addition, subtraction, multiplication and division to 6 significant digits & could solve polynomial equations but was NEVER really completed
Fast ethernet
developed in early 1990s, transmits at 100 Mbps across coaxial cable, fiber-optic cable, or regular twisted-pair copper wire
Ethernet
developed in mid 1970s (xerox PARC research center), designed to operate at 10 Mbps using coaxial cable
Grace Hopper
developed the first compiler for a computer programming language, credited with popularizing the term "debugging", and was a US Navy rear admiral, debunked the common belief that computers could only do arithmetic, popularized the idea of machine-independent programming languages, created COBOL
Repeater
device that simply amplifies and forwards a signal, limited distances
Ports
devices on the Internet have unique IP addresses, computers have many ports (65,535 TCP ports and 65,535 UDP ports) - when a program on your computer sends or receives data over the internet it sends that data to an IP address and a specific port on the computer - programs bind themselves to a port - web servers typically bind to the TCP port 80 - FTP servers use TCP ports 20 and 21
Any given computer needs to support _____ encodings
different
Asymmetric digital subscriber
different upload and download transmission speeds, request messages are small
Primary (storage hierarchy)
directly accessible to the CPU, relatively expensive, RAM (volatile)...access time in nanoseconds, ROM (non-volatile)
Continuous or Discrete
discrete: the state variables change at a finite number of points in time, these events are arranged by the time they should occur, new events are triggered as the previous event is processed & typically run much faster than corresponding continuous simulations - continuous: the state variables change in a continuous way, and there are an infinite # of states
Biometric identifiers
distinctive, measurable characteristics used to label and describe individuals
Lossy compression schemes
do not guarantee that all of the information in the original data can be fully and completely recreated, trade image quality for file size
Unit of resolution
dots per inch, pixels
New FCC Chair suggests changes
download transmission speed: 10 Mbps - upload transmission speed: 1 Mbps
Minimum transmission speeds
download transmission speed: 25 Mbps - upload transmission speed: 3 Mbps
Token-based identification system
driver's license, passport, military ID, mobile device
Randomness
for finite sequences, tests have been developed that verify whether or not the sequence in question shares certain statistical properties with a hypothetical random sequence - frequency, serial, poker, and gap test
Iteration statement examples
for-while loops
PNG - ___ open-source alternative to GIF, __ bit color palette, ___ and ___ bit truecolor, compression is _____, _____ replacement for GIF
free, 8, 24 and 48, lossless, patent-free
Serial test
frequency test applied to 2 digits at a time
Entity
fundamental distinguishable component
Ada Augusta Byron
generally regarded as history's first computer programmer, the Ada programming language was named after her - her notes recognized as the first algorithm to be carried out by a machine - the code was never tested because the Analytical engine was never completed
Modus ponens
gives us a method for making new assertions
Ambiguous statements
go back and do it again (do what again?), start over (from where?), skip ahead (to where?)
Authorization
governs what an authenticated user is allowed to do - user privileges (read, write, execute, and delete access) - system administrator (has access to everything)
History of AI
greek myths, fiction (Blade Runner, Star Trek, Star Wars)
Block cipher
group or block of plaintext letters gets encoded into a block of ciphertext
Types of energy devices
hard disk drives, solid state drives, hybrid drives
Secondary storage devices
hard disk drives..access time in milliseconds, rotating optical devices, flash memory, solid state drives, hybrid drives
Computational modeling
having a major impact on a number of quantitative fields like chemistry, biology, medicine, meteorology etc
Operating systems can be modified without _____
having to scrap the device - security update and system patch
Importance of Broadband
high-definition video conferencing and businesses built around data-intensive products are affected
Taxonomy
how information is classified and organized so customers can easily find what they want
Internet
huge interconnected "network of networks" that includes nodes, LANs, WANs, bridges, routers, and multiple levels of ISPs
After completion of pass 1 and pass 2
object file contains the translated machine language object program
Analog representation
objects can take on any value
4G
offers download speeds of 100 Mbps to 1 Gbps
3G
offers voice services as well as data communication at rates of 0.5 to 2.4 Mbps
Variable length code sets
often used to compress text, can also be used with other forms of data
Bluetooth
often used to support communication between wireless computer peripherals
Sign/magnitude notation
one of a number of different techniques for representing positive and negative whole numbers
Charles Babbage
one of the "fathers of the computer", designed Difference Engine and the Analytic Engine
Image animation
one of the most powerful and useful forms of visualization
Superimpose a grid on an image
only store one color of information for each square of the grid - for a given image, more squares increases the resolution
Bistable environment
only two stable states separated by a huge energy barrier
Expectations of High-Level languages
programmer need not manage details of the movement of data items within memory or pay any attention to exactly where those items are stored, programmer can take a macroscopic view of tasks, thinking at a higher level of problem solving, programs written in a high-level language will be portable, will be closer to natural language
Digital subscriber line (DSL)
provided by either your local telephone company - DSL download speed: 1.5 Mbps - 1 Gbps - typical DSL upload speed: 1-3 Mbps
High-level programming language examples
python and OAMPL
O(n^2)
quadratic run-time
O(n^2) examples
quadratic, bubble sort, selection, insertion sort
Generating random #'s in python
random.random(), random.uniform(), random.randint()
Unicode enables a single software product or website to be targeted across multiple platforms, languages, and countries without ___________
re-engineering
Immutable storage
read only storage (retains information stored at the time of manufacture), write once storage (allows information to be written only once at some point after manufacture - ie. CD-R)
Mutable storage
read/write storage (allows information to be overwritten at any time - ie. RAM, hard disk drives)
LDA 0
reading the input value
RGB True Color
red, green, blue - 8 bits per color, 16.7 million different colors
Individual computers on the network
referred to as nodes, host, or end systems
Computers use binary representation for reasons of ________
reliability
Broadband
replaced modems and analog phone lines for data communication
Run-length encoding
replaces a sequence of identical values (v1, v2..., vn) by a pair of values (v, n)
Operating systems wait for ...
requests and activates other system programs to service these requests
Volatile memory
requires constant power to maintain stored information (DRAM & SRAM)
Knowledge engineering
requires interaction with the human expert, much of it in the domain environment
Symmetric encryption algorithm
requires the use of a secret key known to both the sender and receiver
A _____ must be produced after a finite number of operations
result
John Von Neumann
the father of computer virology (designed a self-producing computer program - world's first virus), a principal member of the Manhattan Project, proposed a radically different computer design based on a model called the stored program computer, part of the research group of UPenn that built one of the first stored program computers called EDVAC in 1951 - also credited with inventing "merge sort"
Herman Hollerith
the father of modern automatic computation, designed and built programmable card-processing machines that could automatically read, tally, and sort data entered on punched cards (censuses), founded the Computer Tabulating Recording Company and in 1924 his company became IBM
Software Development Life Cycle
the feasibility study, problem specification, program design, algorithm selection or development, and analysis, coding, debugging, testing/verification/benchmarking, documentation, maintenance
Artificial Intelligence
the intelligence of machines and the branch of computer science that aims to create it - the study and design of intelligent agents
Turing machines define ______
the limits of computability
Web analytics
the measurement, collection, analysis, and reporting of internet data in order to understand and optimize web usage - collect session-level information about interactions on a website: button clicks, navigation choices, time spent on specific pages, specific outcomes (purchase items, register, etc.)
Known plaintext attack
the plaintext is known by the code breaker
Net Neutrality
the principle that ISPs and the government should treat all data on the internet equally - charge the same price for all users, content, site, platform, application, type of attached equipment and modes of communication
Throughput
the rate at which information can be read from or written to storage - expressed in megabytes per second
Cryptography
the science of "secret writing"
Computer Science
the study of algorithms: their formal and mathematical properties, hardware realizations, linguistic realizations, and applications
Latency
the time it takes to access a particular location in storage
Capacity
the total amount of stored information that a storage device can hold
Virtual memory
this date is retrieved when needed, more retrievals means overall system performance is degraded
Period of the wave (T)
time it takes for the wave to make one complete cycle (units are seconds)
Primary purposes of the first pass of an assembler
to bind all symbolic names to address values, to enter those bindings into the symbol table
Goal of scientific visualization techniques
to take a massive data set and present it in a way that is more informative and more understandable for the user of that data
Frequency (f)
total number of cycles per unit time (units are hertz aka Hz)
Two's Complement representation
total number of values that can represented with n bits is 2^n
Brute force approach for a solution path
traces all branches of the state-space graph
Encryption
transform data from a plaintext to ciphertext and back (a two way operation) - size, word length, length frequency
OAM assembler
translates a symbolic assembly language program into machine language
Summary of an assembler
translates an assembly language program into a machine language program
Gigabit networking
transmission lines that support speeds in excess of 1 billion bits per second (Gbps), typical (consumer) routers come with 1 Gbps ports
Major responsibilities of operating systems
user interface management (a receptionist), control of access to system and files (a security guard), program scheduling and activation (a dispatcher), efficient resource allocation (an efficiency expert), and deadlock detection and error detection (a traffic officer)
Wireless local access network
user transmits from his or her computer to a local wireless base station
Knowledge-based identification system
username and password, PIN #
Two-factor authentication
username and password, receive a security code via text
Examples of authentication
username/password, facial, voice, and fingerprint recognition
Distributed computing environment
users do not need to know the location of a given resource within the network
Problems with machine language
uses binary, is difficult to read, is difficult to change, and is difficult to create data
Robotics
uses for robots in manufacturing, science, the military, and medicine - assembling automobile parts, packaging food and drugs, bomb disposal, welding, radiation and chemical spill detection
Reactive strategy
uses heuristic algorithms to allow the robot to respond directly to stimuli from its environment
Cable modem
uses links that deliver cable TV signals, offered by cable TV providers, typical cable download speed: 10 Mbps - 2 Gbps, typical cable upload speed: 1-3 Mbps
Wireless data communication
uses radio, microwave, and infrared signals
Swarm intelligence model
uses simple agents that: operate independently, can sense certain aspects of their environment, can change their environment
Digital representation
values for a given object are drawn from a finite set
UTF-8
variable byte representation - 1 byte to 4 bytes per code point, first 128 characters are encoded just like ASCII
UTF-16
variable byte representation - 2 bytes to 4 bytes per code point, optimized for languages residing in the 2 byte character range
Location counter
variable used to determine the address of a given instruction
Authentication
verifies who has the right to gain access to the computer
Businesses built around data-intensive products are affected
video streaming services like Netflix and Hulu, call/chat center using VOIP, financial institutions, online retailers, restaurants, and web hosting companies
Types of virtual reality environments and fictional examples
visual, auditory, tactile - Star Trek, The Matrix, Avatar
Conditional statements (P & Q)
→ P is the hypothesis, Q is the conclusion * only time it is False is if P is true and Q is false