Explain and Solve : Round Robin (RR) of Operating System Concepts

If you haven't read/tried the earlier/other problems then click the links follow:

Round Robin: This method is quite same as the FCFS but the difference is the in this case the processor will not process the whole job (process) at a time. Instead, it will complete an amount of job (quantum) at a turn and then will go to the next process and so on. When all job has got a turn, it will again start from the first job and work for a quantum of time/cycle on each job and proceed. Now consider a CPU and also consider a list in which the processes are listed as follows,

Burst Time

Quantum = 2 Second

Explain and Solve : Priority Scheduling of Operating System Concepts

If you haven't read/tried the earlier problems then click the links follow:

Priority Scheduling: This method is quite same as the SJF but the difference is that instead of choosing the next process to work on by the shortest burst time, CPU chooses the next process by the shortest priority value. Here, all the processes are given a priority value. The process with the shortest (The most shortest is 1) priority will be worked on first and so on. Now consider a CPU and also consider a list in which the processes are listed as follows,

Burst Time

Explain and Solve : Shortest Job First (SJF) of Operating System Concepts

If you haven't read/tried the earlier problems then click the links follow:

Shortest Job First (SJF): 

This method is quite same as the FCFS but the difference is the in this case the processor will not process the jobs (processes) as they will come. Instead, a scheduler after a complete cycle (consider this as a 1 second job done) will check which is the job with the shortest burst time right now and will work on that. Now consider a CPU and also consider a list in which the processes are listed as follows,

Burst Time

Explain and Solve : First Come First Served (FCFS) of Operating System Concepts

If you haven't read/tried the earlier problems then click the links follow:

First Come First Served (FCFS): CPU gets a lot of processes to handle. The problem is shortening the waiting time for a process to reach CPU and get processed. Now consider a CPU and also consider a list in which the processes are listed as follows,

Burst Time

My First Use of JavaScript : A Basic Calculator.

Well, I found it that whenever I learn a language the first code I write is always a calculator. I have started taking tutorials on JavaScript few weeks ago to create my own blog, just for fun as I do software engineering on VB.NET platform mainly, that is my site of interest. However, web developing is always interesting to me and I also know that it has a very high level of hard-work and creativity included with it. I don't want to get to that much of details.

On the first day I learnt about using Textboxes, using their values, creating and using functions. Well after that our tutor asked us to do something with what we just learned. Then I wrote the very common 4 functions to do additions, subtractions, multiplications and divisions. Then took two textboxes to take input and another to show result. I also used 4 buttons for the previously mentioned 4 mathematical operations, clicking on each of them the corresponding function will be called. I know its very simple, but I enjoyed.

What I did is a following,

Describe the low pass filter.

Low Pass Filter : Considering the grey-scale values of a part of an image as below,
Here, we have taken 9 grey scale values. It is seen that the 5th value is very different than the other 8 values, that is a big change is occurring at that point due to the big change of the grey-scale value at that point than the other points.

Describe the fundamental steps of digital image processing with a neat block diagram.

Fundamental Steps of Digital Image Processing:

There are some fundamental steps but as they are fundamental, all these steps may have sub-steps. The fundamental steps are described below with a neat diagram.

1. Image Acquisition:

This is the first step or process of the fundamental steps of digital image processing. Image acquisition could be as simple as being given an image that is already in digital form. Generally, the image acquisition stage involves pre-processing, such as scaling etc.

2. Image Enhancement:

Image enhancement is among the simplest and most appealing areas of digital image processing. Basically, the idea behind enhancement techniques is to bring out detail that is obscured, or simply to highlight certain features of interest in an image. Such as, changing brightness & contrast etc.

3. Image Restoration:

Image restoration is an area that also deals with improving the appearance of an image. However, unlike enhancement, which is subjective, image restoration is objective, in the sense that restoration techniques tend to be based on mathematical or probabilistic models of image degradation.

4. Color Image Processing:

Color image processing is an area that has been gaining its importance because of the significant increase in the use of digital images over the Internet. This may include color modeling and processing in a digital domain etc.

5. Wavelets and Multi-Resolution Processing:

Wavelets are the foundation for representing images in various degrees of resolution. Images subdivision successively into smaller regions for data compression and for pyramidal representation.

6. Compression:

Compression deals with techniques for reducing the storage required to save an image or the bandwidth to transmit it. Particularly in the uses of internet it is very much necessary to compress data.


7. Morphological Processing:

Morphological processing deals with tools for extracting image components that are useful in the representation and description of shape.

8. Segmentation:

Segmentation procedures partition an image into its constituent parts or objects. In general, autonomous segmentation is one of the most difficult tasks in digital image processing. A rugged segmentation procedure brings the process a long way toward successful solution of imaging problems that require objects to be identified individually.

9. Representation and Description:

Representation and description almost always follow the output of a segmentation stage, which usually is raw pixel data, constituting either the boundary of a region or all the points in the region itself. Choosing a representation is only part of the solution for transforming raw data into a form suitable for subsequent computer processing. Description deals with extracting attributes that result in some quantitative information of interest or are basic for differentiating one class of objects from another.

10. Object recognition:

Recognition is the process that assigns a label, such as,  “vehicle” to an object based on its descriptors.

11. Knowledge Base:

Knowledge may be as simple as detailing regions of an image where the information of interest is known to be located, thus limiting the search that has to be conducted in seeking that information. The knowledge base also can be quite complex, such as an interrelated list of all major possible defects in a materials inspection problem or an image database containing high-resolution satellite images of a region in connection with change-detection applications.

What is digital image processing?

Digital Image Processing : An image which has a two dimensional function of f(x,y), where x and y are plane co-ordinates and the amplitude of f at any (x,y) is called the grey level of the image at that point. When the values of these of an image are finite, discrete quantities then the image is called a digital image. ... 

Explain Cross Elasticity of Demand.

Cross Elasticity of Demand : Cross elasticity of demand occurs when a change in price of a commodity brings the change in demand of another commodity. The cross elasticity of demand for two goods X and Y, is the ratio of the percentage change of quantity purchased of X to the percentage change in price of Y.

            Cross elasticity of demand occurs for two goods which are interrelated, such as complementary goods, substitutable goods, etc. ... 

Explain Income elasticity of demand.

Income elasticity of demand : A persons demand for a good may change with his\her change in income. The income elasticity of demand is the ratio of percentage change quantity purchased per time to the percentage change in income. Thus,

Explain Price elasticity of demand

Price Elasticity of Demand : Price elasticity of demand measures the quantitative response of demand to a change in price. This is the ratio of percentage change in demand to the percentage change in price. So the price elasticity of demand is,

What is elasticity, elasticity of demand, elastic demand, and inelastic demand?

         Elasticity : In economics, elasticity is the ratio of the percentage change in one variable to the percentage change in another variable. Elasticity is a popular tool among empiricists because it is independent of units and thus simplifies the analysis. ... 

Show the market demand for a commodity with example and explanation.

Market Demand For a Commodity : The market demand for a commodity means the total demand for a commodity made by all the individuals in the market. The market demand for a commodity gives the alternative amounts of a commodity demanded per time period, at various alternative prices, by all the individuals in the market. It depends on all the factors as the individuals demand depends on. It is obtained by the horizontal summation of all the individuals demand curves for the commodity. ... 

What is shift in demand curve? Explain with example.

Shift in Demand Curve : Shift in demand curve means the change in demand curve. This change will have to be for the change in ceteris paribus. That is when the price of a commodity remains constant and the other things which can affect the demand of the commodity changes, a shift can be found in the demand curve. This shift may be either leftward or rightward, meaning the decrease in demand and increase in demand respectively. ... 

Explain the law of negatively sloped demand curve.

Law of Negatively Sloped Demand Curve:

            First, obtain the demand schedule; the formula is,

                                                Qdx = f(Px)

            Considering, an individual demand function for a commodity X is given by,

                                                Qdx =8 - Px    cet.par.

            Here, Qdx  is the quantity demanded and Px is the price of X commodity.

Draw and explain a demand curve by obtaining a demand schedule.

Obtaining Demand Schedule:

To obtain the demand schedule the formula is,

                                                Qdx = f(Px)

Considering, an individual demand function for a commodity X is given by,

                                                Qdx =8 - Px    cet.par.

Here, Qdx  is the quantity demanded and Px is the price of X commodity.

What is / Define Demand, Demand Schedule and Demand Curve.


The desire for a commodity of an individual or a group will be called their demand when they are able to pay for that commodity. That is demand is desire with account to pay.

What is opportunity cost? How / Is opportunity cost related with PPF?

Opportunity Cost:

Life is full of choices. Because resources are scarce, we must always consider how to spend our limited income or time. In a world of scarcity choosing one thing means giving up something else. If there is no increase in productive resources, increasing production of a first good has to entail decreasing production of a second, because resources must be transferred to the first and away from the second. 

What is production possibility frontier (PPF)? Explain.

Production Possibility Frontier (PPF) : In economics, a production possibility frontier (PPF) is a graph that shows the different rates of production of two goods that an individual or group can efficiently produce with limited productive resources. The PPF shows the maximum obtainable amount of one commodity for any given amount of another commodity or composite of all other commodities, given the society's technology and the amount of factors of production available. ... 

What are the differences between microeconomics and macroeconomics?

Differences Between Microeconomics and Macroeconomics: 

The study of economics is divided into microeconomics and macroeconomics by the modern economists. Both of them discuss the economical activities but are used in different sectors under different circumstances. In spit of having some similarities, they also have some differences which have been given below.

What are microeconomics and macroeconomics?

The study of economics is divided into microeconomics and macroeconomics by the modern economists. Both of them discuss the economical activities but are used in different sectors under different circumstances.

What are the three problems of economic organizations? How can the three problems of economic organization be solved in free and mixed economics?

Three Problems of Economic Organizations:

In every economy; economic organizations, irrespective of their type, have to face and solve three problems of economics. These three problems are as follows,

  1. What commodities are produced & in what quantities.
  2. How goods are produced.
  3. For whom goods are produced.

Description and solution to these problems in fee and mixed economies is given below.

Define Economics / Definition of Economics / What is Economics ?

          Economics : The word ‘Economics’ has been originated from the Greek word ‘Oikonomia’ which means ‘Management of household wealth’. As being social, humans face various wants and needs. Economics is all about those activities which occur to fulfill these wants and needs. In fact, Economics describes the economical activities of humans in daily life. Founder of Economics is Adam Smith. ... 

Define the term Solution / What is Solution in Chemistry?

       Solution : Whenever two or more than two non-reacting substances are mixed, the resulting system is called a mixture. A solution is a homogeneous mixture of two or more substances in their molecular level.

Draw the molecular structure of XeF2, XeF4, XeF6.

Xenon forms three stable fluorides, XeF2, XeF4, XeF6. The molecular structure of XeF2 is linear, that of XeF4 is square planar and that of XeF6 is pentagonal pyramidal. They are given in the following figure,

What are inert gases ? why are they so called ?

               Inert gases : The elements of the zero group of the periodic table are known as inert gases. They are also known as noble or rare gases. The inert gases are six in numbers. They are,

Write a short note on Chemical Kinetics.

         Chemical kinetics : The branch of physical chemistry which deals with the study of the speed or rate of chemical reactions and also the explanation of their mechanism is called chemical kinetics.

What do you mean by conjugate acid-base pair ?

           Conjugate acid-base : The base formed by the donation of a single proton by an acid is called the conjugate base of the acid. Similarly, the acid formed by the acceptation of a single proton by a base is called the conjugate acid of the base.

What are the differences between order and molecularity ?

Society, Education, System and WE !!!

Well, the question which is hunting me deep inside for the last 5-7 days, Why I will have to care about others a lot? Why I will have to care about what my father wants me to do, to be? I have my own life, my own choices, then why before taking decisions which are fully related to me, I will have to consider my parents opinions?

Decisions like, side of education, the way of learning, the way of living are all related to me only. What do you think? Should my parents get their hands in it? I don't think so. I should be doing what suits me most. At least when I am a mature person to handle these cases of my life.

Blogspot Tutorial : 4 Easy Steps to Create and Start blogging freely at Blogspot.com or Blogger

Well, This is the first tutorial where we will be creating our blog and will publish one blog post on our free blogspot blog. So lets start..

First of all I would like to say something about Blogspot, subdomain of which we will be using in general. You can buy your own domain, perhaps I am assuming for this tutorial that you will be using a subdomain. For example, if you choose “myblog” as the URL of your blog, your address will be www.myblog.blogspot.com

Becoming a good person, a gentle one I got the title "Jerk", at some cases "Jackass"

Nearly 5 years ago I was a completely different person from the type of person I am now. I was that much of rough as much I am gentle now. I was, you know, a bad, hot temper, rude, trouble maker, ……I don’t know much English, that’s why failing to choose the correct words to describe how I was, but I hope you can understand.

But I left that dark path on 29th October 2006 and never did such kind of bad things from then. I changed completely to someone, completely different.

ভালো হয়ে, ভদ্র হয়ে উপাধি পেলাম - ‌'বোকা', ক্ষেত্রবিশেষে 'বলদ'

আমি আজ যেমন, আজ থেকে বছর চারেকের একটু বেশি আগে ছিলাম ঠিক এর উল্টো। আজ যতটা ভদ্র থাকি আগে ততটাই অভদ্র ছিলাম। এককথায় খারাপ, রগচটা, বেয়াদব, বদমাইশ, বাটপার টাইপের একটা ছেলে ছিলাম। আরো কিছু বিশেষণ যোগ করা যেতে পারতো। তবে ব্লগে লিখা যাবে কিনা ভেবে লিখলাম না।

কিন্তু ২৯ অক্টোবর, ২০০৬ থেকে সেই যে সবকিছু বাদ দিলাম, আজ পর্যন্ত আর সেপথে হাঁটিনি। পুরোটাই বদলে গেছি আমি। 

Watch 1971 er Muktijuddher Itihas by ATN Bangla : The History of the Independence War of 1971 by ATN Bangla

In this post I offere you to watch some videos which were made by Journalists of different countries. Those videos were collected and recently been released as a documentary titled as "1971 er Muktijuddher Itihash by ATN Bangla" [In English - The history of the Independence War of 1971 by ATN Bangla] by a popular news channel "ATN Bangla" of Bangladesh. The commenrty of this video is in Bangla but there many parts where the presidents and journalists and ministers of different countries will be talking in English. Above all, the missereis you will watch will not require any commentry to understand , What hapened and How Happened?

How to write good codes or What are the good programming practices to follow !!

The following post highlights some good programming practices what beginner programmer can follow. Applying these increases the readability of codes, will make make codes more easier to update. 

Well, individual programmers should have their own programming styles to maintain, but still there are some practices that the beginners can follow. With times every programmers find out their own styles. Following is a list of things that beginners can do while coding or solving a problem.

How to merge two sorted arrays? Merging Sort Algorithm, Explanations with Animated Presentation, The Program

Merging Sort: 

Merging sort requires two previously sorted array which will be merged into one single array which will be a sorted array. If the source arrays are not sorted then the algorithm won't work. If you need to sort two unsorted arrays then you can place one array after another then operate the new array with any sorting algorithm to sort it. Another important thing is that, the source arrays will have to be there in sorted in the same order, either ascending or descending.

Bought Sapphire HD 5450 1GB DDR3 PCIE HDMI to Play Mafia II, Review, Full Specification and Links

Well, I don't know much about graphics cards and its features and facts related to performance. Its the first time I bought any graphics card.

Garbage Collection

Garbage collection. What you get from the title of the topic? Well, while we are coding we use variable or memory location. We may need an array initially for storing some initial elements, then we take more arrays while we are manipulating. At some part of the manipulation, it may that we dont need the initial array anymore. I mean it may that we have already took all the elements of the initial array and processed and stored them in another array for furthur processing and dont need the initial array anymore. However, that initial array still remains eating up some memory locations.

Understanding Variable scope in C++

Understanding Variable scope is very important because it can sometime leads us to unwanted value changing or hazards while coding. Like, we have declared a variable but still its showing error while compiling or running. Look at the following code,

for(int x=0;x<5;x++)    //For Loop 01
   cout<<"Inside For Loop 01";
cout<<x<<" times";    //Line01  

When we will compile this code we get some kind of error msg which may vary from compiler to compiler, but in general the error msg will be related to the variable x.

Allocating and Deallocating memory OR use of New/Delete OR allocating memory in runtime OR declaring array in runtime | in C++

Well, first of all we should be known with Variable Scope, Garbage Collection.

Ok, now. When we declare a variable like as follows,

int a;

it allocates a specific portion of memory for that variable and when we go beyond the scope of the variable the garbage collection system automatically deallocates or in general, deletes the memory location which was occupied by the variable.

But in some cases, like when declaring an array, we might need to allocate a number of array elements which we don’t and which will be specified by the user at the runtime. In such a case we have to declare the array with the number of elements given by the user. Here, we can use the new operator as follows,

Single Layer Perceptron Learning Algorithm and Flowchart of the Program and the Code of the Program in C++

The Single Layer Perceptron Learning Algorithm:

Step 1:        Initialize all weights and threshold and values.
Step 2:        Get the weighted sum of one input.
Step 3:        Compare the weighted sum with the threshold and set value to output.
Step 4:        If the input is of class A

My Works | Final working on my Expression Based Scientific Calculator, hoping to finish tonight

My expression based scientific calculator V 0.03 is 80 percent complete. I was thinking that I will add more options to it, but sorry to say that its much boring to me now. However, here are some screenshots of the software, leave your comment about these.

The Calculator Front

Tutorial :: Creating a LogIn/Registration Form for your software [Basic]

For whom the tutorial is: Well, I am sorry that this is not for beginners. I mean, when I started writing I thought I will explain each lines of code in this tutorial but, you know it’s impossible for me and I am sorry. So, if you are a complete beginner it will be hard for you to understand.

01.   You should have knowledge about creating functions and their usages.
02.   You should have knowledge about connecting MS Access Databases with VB.NET08.
03.   You should have knowledge about SQL Queries.
04.   You should have basic knowledge about the program structure of VB.NET08

Well, for your interest you can keep this tutorial, try to understand it. Read the following lines to understand what I have done in the code.

The Structure of Program: Well, welcome to this tutorial where we will be building a form for the purpose of “Login of existing users and Registrations of new user”.

Addressing 5 ROM Chips, Each of 4 KB Using 74LS138 Decoder

Addressing 5 ROM Chips, Each of 4 KB Using 74LS138 Decoder:

The following diagram is representing the addressing of 5 ROM chips using 74LS138 where each chip is of 4 KB.

How can we interface the microprocessor with analog world? Explain with necessary figure.

Interfacing the Microprocessor with Analog World: As computer used digital binary values whereas we have physical variables, a step by step process is used to convert the physical variable to binary data and again to physical variable. The figure is given below

How can you control LEDs using microprocessor via 82C55A PPI? Draw the interface diagram & write the necessary assembly codes.

Controlling LEDs Using Microprocessor VIA 82C55A:

What are the purpose of using command byte A and command byte B on 82C55A? Explain with suitable example.

Purpose of Using Command Byte A: Command byte A is used select modes, working functions of the ports. So the importance of using command byte A is that we can define on which mode it will be working on and which port will be used for which function such as input or output.

For example, consider the following bit format

What will be the arrangement of ports on 82C55A PPI for the following bit format of command byte A, 10000010

The given bit format is as follows,


Arrangement of Ports Due to Given Bit Format:

What will be the bit format of command byte A in 82C55A PPI for these arrangement, (i) Mode 0, Port A as input, port B and port C as output. (ii) Mode 1, port A as output, port B as input.

(i) Required Bit Format of command byte A: 

Draw the command byte A and command byte B of 82C55A PPI.

Command Byte A and Command Byte B:

Draw the pin-out diagram of 82C55A PPI. How many modes you can select on 82C55A PPI? Explain.

Pin-Out Diagram of 82C55A:

What is handshaking? Write a suitable example for handshaking with necessary assembly codes.


Handshaking is a I/O control method to synchronize I/O devices with the microprocessor. As many I/O devices accepts or release information at a much slower rate than the microprocessor, this method is used to control the microprocessor to work with a I/O device at the I/O devices data transfer rate.

Write the differences between Isolated I/O and Memory Mapped I/O.

Memory Mapped I/O and Isolated I/O are two methods of performing input-output operations between CPU and installed peripherals in the system. Memory mapped I/O uses the same address bus to connect both primary memory and memory of hardware devices. Thus the instruction to address a section or portion or segment of RAM can also be used to address a memory location of a hardware device.

On the other hand, isolated I/O uses separate instruction classes to access primary memory and device memory. In this case, I/O devices have separate address space either by separate I/O pin on CPU or by entire separate bus. As it separates general memory addresses with I/O devices, it is called isolated I/O.

Define port? Differentiate fixed port addressing and variable port addressing.

          Port : A port is an adapter which enables a system to communicate with its input/output devices. Using port user can connect I/O devices and use them. There various types of port such as parallel port, serial port etc.

            Differences Between Fixed Port and Variable Port Addressing