The relational algebra expressions can be rearranged and achieve the same result but with a better processing time. A selection on an attribute can be moved from the outside of a query to a selection on just one of the relations being joined (if it isn't an attribute on both relations). Why would this be an improvement?
a. The selection on the joined results would cause a cartesian product operation
b. Moving the selection to the innermost relation keeps the depth of operations that have to be processed more shallow
c. This would reduce the number of tuples to involve in the join resulting in a more efficient query.
d. The outer selection would prevent the optimizer from picking the correct index

Answer:

A. Is a distributed file system

Explanation:

The WAFL is a distributed file system. It is blocked based and it has to make use of inodes to describe it's files. This is a proprietary file system, ystem layout. The WAFL makes use of files for the storage of meta-data which gives a description of the layout of the file system.

The WAFL is named the Write Anywhere File Layout because all data can be written in any part on the disk.

Answer:

Technology has altered human physiology. It makes us think differently, feel differently, even dream differently. It affects our memory, attention spans and sleep cycles. This is attributed to a scientific phenomenon known as neuroplasticity, or the brain's ability to alter its behavior based on new experiences.

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Answer:

D) Static method

Explanation:

A static method is a method that is created only for the class and not it's instance variables or objects. Such methods can only be accessed by calling them through the class's name because they are not available to any class instance. A static method is created by prefixing the method's name with the keyword static.

A static method cannot be overridden or changed. You create a static method for a block of code that is not dependent on instance creation and that can easily be shared by all instances or objects.

Solution :

#include <iostream>

#include <iomanip>

using namespace std;

int main()

{

   //declaring variables

   int mile, hours ,minute;

   char option='Y';

   float fuel;

   //display welcome message

   cout<<"Aircraft Fuel Calculator\n\n";

   //this loop will run untill user enter Y or y

   while(option=='Y' || option=='y'){

   //asking user to enter miles

       cout<<"Distance in nautical miles : ";

       cin>>miles;

       //calculating hour and minutes

       hour=miles/120;

       minutes=(miles%120)/2;

       //setting 1 decimal place

       cout << fixed << setprecision(1);

       fuel=(miles/120.0 + 0.5)*8.4;

       //display data

       cout<<"Flight time: "<<hour<<" hour(s) and "<<minutes<<" minute(s)"<<endl;

       cout<<"Required fuel: "<<fuel<<" gallons\n\n";

       cout<<"Continue? (y/n): ";

       cin>>option;

       cout<<"\n";

   }

   cout << "Bye!" << endl;

   return 0;

Answer:

It would basically be based on how you study and what your room is like. But my opinion would be

Bedrooms are Too Comfortable- which causes you to want to sleep or not due your work

Bedrooms are dimly lit- Which makes it hard for you to see your work and see anything

Bedrooms are too small- You will fell crushed and hard to focus (I would most likely choose this answer)

Bedrooms are messy and cluttered- You will not be able to concentrate and make it hard to study or do school work. ( I would choose this because I have experienced with this and I score higher in a cleaner environment and able to focus more)

Explanation: This would all depend on how you best work.

Hope this Helps!!

Answer:

A

Explanation:

Vector graphics consist of mathematical descriptions of shapes as a combination of these numerical vectors. Because the vector graphics define the path that the lines should take, rather than a set of points along the way, they can be used to calculate any number of points, and so can be used at any image resolution.

The characteristics of vector graphics are they are based on mathematical/geometric expression. The correct option is A.

Vector graphics are mathematical descriptions of shapes created by combining these numerical vectors. Because vector graphics indicate the course that the lines should travel rather than a set of locations along the way, they may be used to calculate any number of points and thus work at any image resolution.

Raster images generate commonly used image files such as gif, jpeg, jpg, and so on. These can be made with picture editing software such as "Photoshop." Because these work on pixels, when we zoom the image, we can see tiny squares that are nothing more than pixels.

Therefore, the correct option is A, they are based on mathematical/geometric expression.

To learn more about vector graphics, refer to the link:

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Answer:

The answer to this question is given in the explanation section.

Explanation:

C# uses the struct keyword to declare structure.

The are used to store related data item.

For example the record of Student i-e his name, father name, address and class no can be declared using structure

using system

struct Student {

  public string name;

  public string father_name;

  public string address;

  public int class_no;

};

Answer:

Explanation:

We start from the bottom-most and rightmost internal node of min Heap and then heapify all internal modes in the bottom-up way to build the Max heap.

To build a heap, the following algorithm is implemented for any input array.

BUILD-HEAP(A)

   heapsize := size(A)

   for i := floor(heapsize/2) downto 1

       do HEAPIFY(A, i)

   end for

Convert the given array of elements into an almost complete binary tree.

Ensure that the tree is a max heap.

Check that every non-leaf node contains a greater or equal value element than its child nodes.

If there exists any node that does not satisfy the ordering property of max heap, swap the elements.

Start checking from a non-leaf node with the highest index (bottom to top and right to left).

Answer:

eye contact

Explanation:

Answer:

3. D: px

4. B: web page

Explanation:

All font sizes are measured in px unless specified otherwise (in em's for example).

The correct answer is a web page because itself is a unique file that displays multimedia components.

Answer:

Q3: Font size is measured in pt (point)  which can be converted into centimeter(cm)

Q4: The answer is webpage

Explanation:

Q3: Font size is measured in pt (point)  which can be converted into centimeter(cm)

Q4: A unique file with unique name and address is  a webpage.

because webserver and browser are software while website is collection of webpages.

So that people with strengths in different areas can work on what they do best, plus it divides the workload.

Answer:

#include <iostream>

#include <cstdlib>

#include <ctime>

using namespace std;

int main(){

   int n;

   cout<< "Enter the row and column length: ";

   cin>> n;

   int array_one[n][n];

   int array_transpose[n][n];

   for (int i = 0; i < n; i++){

      for (int j= 0; j < n; j++){

           srand((unsigned) time(0));

           array_one[i][j] = (rand() % 4000)

           array_transpose[j][i] = array_one[i][j];

       }

   }

}

Explanation:

The C source code has three variables, 'array_one', array_transpose' (both of which are square 2-dimensional arrays), and 'n' which is the row and column length.

The program loops n time for each nth number of the n size to assign value to the two-dimensional array_one. the assign values to the array_transpose, reverse the 'i' and 'j' values to the two for statements for array_one to 'j' and 'i'.

Answer:

Spectrem

Explanation:

Answer:

The Unix core used in Apple's macOS is called Darwin which is similar to the BSD Unix operating system. The Darwin in macOS has evolved, providing a slick aqua-graphical user interface for users to interact with the application by clicking rather than writing Unix commands in terminals.

Explanation:

The macOS is the operating system used by Apple computer brands. The operating system is a subset of the Unix's BSD operating system. It still makes use of the traditional Unix terminal and scripts but with a few alterations.

The significance of the UNIX core of macOS can be briefly described as:

This refers to the different kernel subsystems which are a part of the process management and memory allocation of a device.

Hence, the significance of the UNIX core of macOS has made it very easy for Apple users to communicate with their device in real time and also to power the phone.

Read more about UNIX here:

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Answer:

def cord_input():

Global coordinates

coordinates = {'x1': 0, 'y1': 0, 'x2':0, 'y2':0, 'x3':0, 'y3':0}

for key, i in enumerate(coordinates.keys()):

if i < 2:

index = 1

coordinates [key] = float(input(f"Enter {key} coordinate for point {index}: "))

elif i >= 2 and i < 4:

index = 2

coordinates [key] = float(input(f"Enter {key} coordinate for point {index}: "))

else:

index = 3

coordinates [key] = float(input(f"Enter {key} coordinate for point {index}: "))

def sides(p1, p2, p3):

nonlocal a, b, c

a = ((p2[0] - p1[0])**2) + ((p2[1] - p1[1])**2)

b = ((p3[0] - p2[0])**2) + ((p3[1] - p2[1])**2)

c = ((p3[0] -p1[0])**2) + ((p3[1] - p2[1])**2)

def is_right_triangle(p1, p2, p3):

sides(p1, p2, p3)

if a+b == c or b+c == a or a+c == b:

print(f"Sides {a}, {b} and {c}")

return True

else:

return False

def is_equilateral(p1, p2, p3):

sides(p1, p2, p3)

if a==b and b==c:

print(f"Sides {a}, {b} and {c}")

return True

else:

return False

cord_input()

Explanation:

The python code above defines four functions, cord_input (to input a global dictionary of coordinates), sides ( to calculate and assign the sides of the triangle), is_right_triangle ( to check if the coordinates are for a right-angle triangle), and is_equilateral for equilateral triangle check.

Answer:

- Iterate over the Bellman-Ford algorithm n-1 time while tracking the parent vertex and store in an array.

- Do another iteration and if no relaxation of the edges occurs in the nth iteration then print of return "There are no negative cycle".

- Else, store the vertex of the relaxed edge at the nth iteration with a variable name.

- Then iterate over the vertexes starting from the store vertex until a cycle is found then print it out as the cycle of negative weight.

Explanation:

The Bellman-Ford algorithm can be used to detect a negative cycle in a graph. The program should iterate over the algorithm, in search of a relaxed edge. If any, the vertex of the specified edge is used as a starting point to get the target negative cycle.

Answer:

Option 4: 50 is the correct answer.

Explanation:

Arithmetic operations can be performed using the programming languages. Some symbols used in programming languages are different from what we use in mathematics.

The symbol * is used to represent multiplication in programming languages.

Given

A = 5

B = 10

So, A*B will be equal to: 5*10 = 50

Hence,

Option 4: 50 is the correct answer.

Answer:

dd if=/dev/drive1 of=/dev/backup

Explanation:

Linux operating system is an open-source computer application readily available to system operators. The terminal is a platform in the operating system used to write scripts like bash and directly communicate with the system kernel.

There are two commands used in bash to copy files, the "cp" and "dd". The dd is mostly used to copy files from one storage or partition to another. The syntax of dd is;

dd if= (source partition/directory) of= (target partition/directory)

Answer:

import javax.swing.JPanel;

import javax.swing.JOptionPane;

import javax.swing.JFrame;

import javax.swing.JLabel;  

import javax.swing.JTextField;

import javax.swing.border.Border;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import javax.swing.BorderFactory;

import javax.swing.JButton;

import java.awt.BorderLayout;

import java.awt.Color;

import java.awt.FlowLayout;

import java.awt.Graphics;

import java.awt.Rectangle;

public class DrawingPanel{

private static final int width = 800;

private static final int heigth = 500;

private static JFrame mainFrame;

private static JPanel mainPanel, inputPanel, drawPanel;

private static JLabel xLabel, yLabel;

private static JTextField xField, yField;

private static JButton drawButton;

public static void main(String[] args)

{

mainFrame = new JFrame("Draw Path");

mainPanel = new JPanel(new BorderLayout());

inputPanel = new JPanel(new FlowLayout(FlowLayout.CENTER));

xLabel = new JLabel("X Coordinate: ");

xField = new JTextField(5);

yLabel = new JLabel("Y Coordinate: ");

yField = new JTextField(5);

drawButton = new JButton("Draw");

inputPanel.add(xLabel);

inputPanel.add(xField);

inputPanel.add(yLabel);

inputPanel.add(yField);

inputPanel.add(drawButton);

Border border = BorderFactory.createLineBorder(Color.black);

drawPanel = new JPanel(new FlowLayout(FlowLayout.CENTER));

drawPanel.setBorder(border);

mainPanel.add(inputPanel, BorderLayout.NORTH);

mainPanel.add(drawPanel, BorderLayout.CENTER);

mainFrame.add(mainPanel);

mainFrame.setSize(PANEL_WIDTH, PANEL_HEIGHT);

mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

mainFrame.setLocationRelativeTo(null);

mainFrame.setResizable(false);

mainFrame.setVisible(true);

// action listener for draw button

drawButton.addActionListener(new ActionListener() {

(use the at sign here)Override

public void actionPerformed(ActionEvent e) {

if(xField.getText().equals("") || yField.getText().equals(""))

JOptionPane.showMessageDialog(null, "Please enter the x and y coordinates!");

else

{

int x2 = Integer.parseInt(xField.getText().trim());

int y2 = Integer.parseInt(yField.getText().trim());

if(x2 > WIDTH || y2 > HEIGHT)

JOptionPane.showMessageDialog(null, "x and y coordinates should be less than "

+ width + " and " + height + " respectively!");

else

drawPath(x2, y2);

}

}

});

}

public static void drawPath(int x2, int y2)

{

int x1 = (int)drawPanel.getBounds().getCenterX();

int y1 = (int)drawPanel.getBounds().getCenterY();

Graphics g = drawPanel.getGraphics();

Rectangle r = drawPanel.getBounds();

g.setColor(drawPanel.getBackground());

g.fillRect(r.x, r.y, r.width, r.height);

g.setColor(Color. blue);

g.drawLine(x1, y1, x2, y2);

}

}

Explanation:

The class DrawingPanel is a Java class that gets the user input for the coordinate of a path with predetermined heigth and width (defined in the class). The methods of the class are; getGraphics(), getBounds(), getBackground(), setColor() and fillRect(). The result is a rectangular path GUI on the screen.

Answer:

import numpy as np

word = input("Enter a word: ")

acc = []

with open("Downloads/record-collection.txt", "r") as file:

   lines = file.readlines()

   for line in lines:

       if word in line:

           line = line.strip()

           acc.append(int(line[0]))

   if np.mean(acc) >= 2:

       print(f"The word {word} is a positive word")

       print(f"{word} appeared {len(acc)} times")

       print(f"the review of the word {word} is {round(np.mean(acc), 2)}")

   else:

       print(f"the word {word} is a negative word with review\

{round(np.mean(acc), 2)}")

Explanation:

The python program gets the text from the review file, using the user input word to get the definition of reviews based on the word, whether positive or negative.

The program uses the 'with' keyword to open the file and created the acc variable to hold the reviews gotten. The mean of the acc is calculated with the numpy mean method and if the mean is equal to or greater than 2 it is a positive word, else negative.

Answer:

They meet required amount of traffic or clicks.

Explanation:

AdSense is an advertisement platform for businesses. It advertises the registered business on various target client platform like mobile app and web app who allow these adverts for profit with a commission rate for a certain amount of traffic generated from the platform on the advertised business.

Answer:

a

the most suitable answer

Answer: a replay attack, a replay attack is used so that the attacker can go sniff out the hash, and get whatever they are trying to get, then once it goes to the attacker it will go back to the original connection after replaying the hash

Hackers use packet sniffing attacks to intercept or steal potentially unprotected data from networks. A network-generated threat is a sniffing attack, also known as a packet sniffing assault. Thus, option D is correct.

Snooping gives ethical hackers a lot of information about how a network functions and how its users behave, which can be used to improve a company's cybersecurity.

Sniffing can, however, be utilized by unscrupulous hackers to conduct catastrophic attacks against gullible targets.

A network sniffer can detect someone using excessive bandwidth at a college or commercial organization and hunt them down.

Therefore, replay attacks are employed so that the attacker can find the hash and obtain the desired object. Once the attacker has received the object, the replay attack causes the object to return to the original connection.

Learn more about  sniffing network here:

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Answer:

public class GiftBox{

private int length;

private int width;

private int height;

public GiftBox(double length, double width, double height) {

this.length = length;

this.width = width;

this.height = height;

}

public static GiftBox getNewBox(GiftBox giftBox, double m) {

return new GiftBox(m * giftBox.length, m * giftBox.width, m * giftBox.height);

}

private boolean fitsInside(GiftBox giftBox) {

if(giftBox.length < this.length && giftBox.width <this.width

&& giftBox.height < this.height) {

return true;

}

return false;

}

public static void main(String []args){

GiftBox giftBox = new GiftBox(3.0 , 4.0, 5.0);

GiftBox newGiftBox = getNewBox(giftBox, 0.5);

System.out.println("New Box length: " + newGiftBox.length);

System.out.println("New Box width: " + newGiftBox.width);

System.out.println("New Box height: " + newGiftBox.height);

GiftBox gift = new GiftBox(3.0 , 4.0, 5.0);

GiftBox other = new GiftBox(2.1 , 3.2, 4.3);

GiftBox yetAnother = new GiftBox(2.0 , 5.0, 4.0);

System.out.println(gift.fitsInside(other));

System.out.println(gift.fitsInside(yetAnother));

}

}

Explanation:

The getNewBox is a public method in the GiftBox class in the Java source code above. It returns the GiftBox object instance increasing or multiplying the dimensions by the value of m of type double.

Answer:

B. Ram

Explanation:

A random access memory (RAM) can be defined as the internal hardware memory which allows data to be read and written (changed) in a computer. Basically, a random access memory (RAM) is used for temporarily storing data such as software programs, operating system (OS), machine code and working data (data in current use) so that they are easily and rapidly accessible to the central processing unit (CPU).

Additionally, RAM is a volatile memory because any data stored in it would be lost or erased once the computer is turned off. Thus, it can only retain data while the computer is turned on and as such is considered to be a short-term memory.

There are two (2) main types of random access memory (RAM) and these are;

1. Static Random Access Memory (SRAM).

2. Dynamic Random Access Memory (DRAM).

Given a physical host machine that has four quad-core central processing units (CPUs), 16GB of random access memory (RAM), 1TB of hard drive space, and two 1Gbps network interface cards (NICs). Therefore, if we need to create four Windows 2008 servers, the first bottleneck we should upgrade is the random access memory (RAM) because it is typically the working memory that would be used by the server to store data, so they can be accessed easily and rapidly by the central processing unit (CPU).

Hence, the random access memory (RAM) may be increased from 16GB to 64GB or more depending on the client's requirements.

Answer:

A

Explanation:

A. Makes the the most sense

B. Not exactly

C. Doesn't make any sense

D. Complete Garbage