CS504 VU Current Assignment No. 3 Fall 2011

Question: [marks 10+10]

Consider a community website e.g. Facebook.com, which the people from different communities can use to share their status, videos, images, articles etc. with each other.

To use the website a person must be registered member, and for registration the user must have an email address on Gmail, Yahoo or Hotmail (But no other domain).

After registration the person becomes the member of the community, and can share anything with his/her friends.

However to make a friend he/she can have two options:

1) He/she can use the search service provided by the website to search friends (already members of the site), to which he sends the “friend request”, after that person (to whom the request was sent) accepts the request, they both become friends and can share anything with each other.

2) Secondly he/she can select the option “Find friends using email contacts”. In this case the system fetches the contact list from his email account; requests are automatically sent to the persons that are already added in his/her email contacts (and are also the member of this community website). When all these members accept requests they become friends of the requester and can share anything with him/her.

Keeping in mind the Krutchen’s 4+1 architectural view model, develop diagrams to represent (at least one diagram for each):

1) Implementation view (Also called Development View or Code view)

2) Deployment View (Also called Physical view)

Note: you can use any notations and any software to draw the diagrams. For further concepts about Architectural Views, please revise Lecture no. 23

Deployment View:

The deployment view / physical view describe how the system is deployed in terms of its hardware resources [1]

Here in above diagram:

Client PC: is the any client system (desktop PC or mobile even) with a browser (client) application running on it. Members login to the registration server by providing their login information.

Registration Server: Registration server is the central database server (may be a mainframe system) with multiple processes (e.g. login validation and authentication process, contents management process, security related processes, external interface managers etc. etc.), running on it for overall operational site.

External / Remote Server: May be external server e.g. a Google server or Hotmail server etc. which is contacted by the internal (website registration server) through secure communication and interfaces to get needed information e.g. contact lists etc.

Implementation / Code View:

The code view is what a programmer sees. Thus the components of this view are things like classes, objects, procedures, and functions and their abstraction/composition into things like subsystems, layers and modules [1]. For the sake of simplicity we present a top level view of system in terms of main components and sub-components (up to first level only)

References :

[1] “Evaluating software Architectures: Methods and Case Studies”, by Paul Clements,

Rick Kazman, and Mark Klein. 2002 Addison-Wesley.

CS101 Assignment #01 Solution

Solution:

Q.1. There are multiple ways to enhance the performance of a computer system. Discuss what role a cache can play in boosting up the performance of a computer system? (5 Marks)

Answer:
A CPU cache is a cache used by the central processing unit of a computer to reduce the average time to access memory it is different as compare to the main memory which is used to copy data from the secondary storage it store the data inside the page file and then take it from there as compare to cache memory it exists inside the cpu and directly gives the data to cpu to process the instructions lets see a figure which will make it more clear. The cache is a smaller, faster memory which stores copies of the data from the most frequently used main memory locations. As long as most memory accesses are cached memory locations, the average latency of memory accesses will be closer to the cache latency than to the latency of main memory. It is Volatile memory, also known as volatile storage, is computer memory that requires power to maintain the stored information, When the processor needs to read from or write to a location in main memory, it first checks whether a copy of that data is in the cache. If so, the processor immediately reads from or writes to the cache, which is much faster than reading from or writing to main memory. Most modern desktop and server CPUs have at least three independent caches: an instruction cache to speed up executable instruction fetch, a data cache to speed up data fetch and store, and a translation [vu solutions] look aside buffer (TLB) used to speed up virtual-to-physical address translation for both executable instructions and data. Data cache is usually organized as a hierarchy of more cache levels which are L1 and L2 etc.

Q.2. Generally there is a concept that “Memory” and “Storage” are same terms. Do you agree? Justify your opinion with a real life example. (5 Marks)

Answer:
AS we know nowadays these are very common terms which we use in our daily life so for that you called mostly the Ram as the memory of the system and the Storage device which is called the hard disk or Flash (Usb) memory or can be a memory card. So what’s the difference between them lets see it in real life that in Memory which is Volatile and need powers to maintain if the electricity is off then it is going to wash each and everything. As compare to the Storage Non-Volatile memory which doesn’t need the power all the time when the data is store to it and power went off next time you can see the data inside it. As we can see a new functions which start from the Xp Windows Os from Microsoft. Hibernate it store the data to the hard drive from the Memory You can say the Memory to storage when you hibernate the system it will open next time all the files and applications where you were working. So it’s an example from real life.

Q3).Convert the following Octal Number to Hexadecimal Number by writing each and every step of conversion process: (5 Marks) (53324)8 => (?)16

First we will convert this to binary to decimal

STA630 Online Quiz No. 1 Fall 2011 Announcement

Online Quiz # 01

All Students of Fall Semester 2011 are informed that Online Quiz # 01 for

“Research Methods (STA630)” will be uploaded according to the following schedule:

Opening Date and Time : October 31, 2011 At 12:01 AM

Closing Date and Time : November 01, 2011 At 11:59 PM

CS506 Assignment No. 1 Fall 2011 Solution

Question:

Write a program that computes the average and standard deviation of the text floating point numbers in a file. Use the following formulas for the average and the standard deviation of N values. The formulas compute the sum, the sum of squares, the average, the average square, the variance, and finally, the standard deviation.

sum = x1 + x2 + x3 + ... + xN-1 + xN

sumSQ = x12 + x22 + x32 + ... + xN-12 + xN2

avg = sum/N

avgSQ = sumSQ/N

var = avgSQ - avg2

sd = var(1/2)

The input file will contain any number text floating point numbers, similar to the following:

10.5

12.9

9.67

12.05

8.23

10.08

10.23

7.7

10.4

11.34

Numbers could be several, or none per line, and negative numbers are perfectly OK.

Solution:

Input Text:

10.0

20.0

30.0

40.0

50.0

............

SAVE THIS FILE IN .JAVA

import java.io.*;

import java.util.*;

import javax.swing.*;

public class assignment1{

public static void main( String args[] ){

try{

FileReader fr = null;

BufferedReader br = null;

fr = new FileReader ("input.txt");

br = new BufferedReader (fr);

String line = br.readLine();

double sum =0 ;

while (line != null) {

double num = Double.parseDouble(line);

sum += num;

line = br.readLine();

}

JOptionPane.showMessageDialog(null, "Sum = " + sum);

br.close();

fr.close();

}

catch(NumberFormatException nfEx) {

System.out.println(nfEx);

}

catch(FileNotFoundException fnfEx){

System.out.println(fnfEx);

}

catch(IOException ioEx){

System.out.println(ioEx);

}

}

}

Fin622 Assignment No. 1 Fall 2011 solution

ABC corporation stock is selling for Rs. 150 per share according to Karachi stock exchange market summary. A rumor about the company has been heard that the firm will make an exciting new product announcement next week. By studying the industry, it is being concluded that this new product will support a growth rate of 20% in dividend for two years. After that it is expected that the growth rate in dividend will decline to 6% and remains same onwards. The firm currently pays an annual dividend of Rs. 4.

The rate of return on stocks like ABC Corporation is 10%.

Required:

I. Find out the values for D1, D2 and D3 (8 Marks)

II. What will be the price of stock (P2) at the end of year 2? (4 Marks)

III. What will be the present value (P0) of stock? (6 Marks)

IV. Should we buy stocks of ABC Corporation at Rs. 150? (2 Marks)

Solution

Find out the values for D1, D2 and D3

D1= 4 (1+0.2) =4.8

D2= 4.8 (1+0.2) =5.76

D3=5.76 (1+0.05) =6.11

What will be the price of stock (P2) at the end of year 2?

P2= 5.76 (1+0.2)/ .1-0.05

P2=138.24

What will be the present value (P0) of stock?

PO= 4.8/(1+.1)1 + 5.76/(1+.1)2 + 6.11/(1+.1)3 + 128.31/(1.1)3

= 110

Should we buy stocks of ABC Corporation at Rs. 150

As the present value of the stock is less then the current selling price so the stock should not be purchased.