Tuesday, November 30, 2010

Education an Business

Education is important to the family as well as to the country. Education is more having a land more than acres. When one got the proper education he can survive anywhere in this world. In the olden days the education is like an service. Many people had spend their whole life for education. But in nowadays the whole situation has changed. The Education has become the business. People are starting the schools and colleges for earning money only. Providing the education has become secondary. The new colleges and the schools are opening with the aim of earning money. In Chennai for my friend sister’s daughter LKG admission they paid Rs.50000. After that term fees, tuition fee, sports fee and many other fees. For colleges even more high. For the engineering college the donation is vary from Rs.100,000 to Rs.2,500,000. Most of the colleges are started by the politicians. In Tamilnadu alone there are more than 600 Engineering colleges are there. People got very less marks also get admission in engineering colleges and in the medical colleges by paying money to the colleges. The result is the students will not shine in college also and at the last the Unemployment has arise. By the latest trend everyone is going to study Engineering and the admission in other fields has reduced. Due to this competition has increased in the engineering filed and in other field the companies are struggling to get the employees. According to a census the ratio of unemployment in engineering is higher than other fields in India. Government has not taken any steps to this situation. They are allowing to built more engineering. Every politician is looking for the money. Instead of this they can introduce other courses that is not available in India. They can take steps to implement the educational courses that is not available in India. Agriculture is the backbone of India. But the agriculture is dying. They can introduce the R&D for the agriculture field and make the students attention towards agriculture. Even we are in Software field, we cannot program to produce the food or we cannot eat he computers. We can eat only the rice and wheat. Education is needed for everyone but the education should be helpful for the nation’s growth in all the aspects. Our body will be look healthy only if all our parts are healthy. If only one part was healthy, then it is a disease.

Saturday, November 20, 2010

Trick to browse 20 times faster

If you have the low speed internet connection I am sure you will search for the software to browse faster. Here is the trick to browse 20 times faster with your slow connection without any software tool. Follow the simple procedure to fast your connection. It will take just 2 minutes.
1.       Open the command mode and type gpedit.msc as shown below.

2.                   Then select the Administrative template from computer Configuration.

3.                    Double click on “Network“and then double click on “QoS Packet Scheduler”. 

 Double click on “Limit Reservable Bandwidth”. It will open a window. 

  Click on “Enabled” radio button and set the bandwidth limit to “0%” which was “20%” earlier. Finally click on “Apply” >> “OK” button. 

    That’s all. Restart your computer and browse 20 times faster than before. This trick works from windows XP version. I did the same trick with my Windows 7 and I am browsing faster than before.

Sunday, November 14, 2010

Tips to Utilize the study holidays (or) Ways to score good marks in Exams

Every student will get afraid of the exams. Even the brightest student will get afraid when the exam days nearing. I am going to provide you the tips to utilize the study holidays before the exam starts. Every university will provide some time to prepare for the exams before the exam starts. It may be one week or two week or some time it may be one month. If you utilized the study holidays you don’t want to get afraid of the exams and you will clear all the exams without any arrears. Follow the below steps to utilize the study holidays.
1.       Calculate how many days leave they are providing for the study holidays.
2.       Divide the days for the total number of subjects you have. (ex. If you got 15 days leave and you have 5 subjects 15/5 = 3 days for a subject).
3.       Now plan for the 3 days to complete the subject in time.
4.       Split up the days as follows.
5.       Study for 12 hours a day. Sleep for 8 hours and 4 hours to relax you.  In that four hours relaxation play for 1 hour listen to music for 1 hour and 2 hours of your wish. The important thing is don’t take 4 hours continuously. Take one hour continuously and split the break hours for four times.
6.       Plan the 12 hours perfectly. Split the time to study a question or the subject. (I usually take 5 hours to finish a subject.) Set the target for yourself and start.
7.       The best time to study is the morning hours and in the evening hours. Wake up by 5.30 or 6 am and start studying till 10’o clock. After that you will get bored.
8.       Take a break of one hour for bathing and have your breakfast for 45 minutes. Have fun in the remaining 15 mins and go back to study.
9.       Study up to 1’o clock and have your lunch have a small sleep and go back to study at 4 pm. Sleep for 2 hours in this 3 hours break.
10.   Study till 6’o clock and have a break for the tea and have some fun around you for one hour.
11.   Start studying at 7’o clock and study till 9’o clock. Take one hour break for the dinner and watch some shows on TV.
12.   Go back to studying at 10’o clock and study till 12’o clock in night. Go to bed and wake up in the next morning at 6’o clock and continue the same procedure for the next days.
If you follow this procedure you will surely finish all your subjects in time and you will have sufficient time during the exam time to revise your subjects. I followed the same above strategy from the 3rd year of my engineering and I got succeed with this technique. I got plenty of time during my exams. I will go to bed by 10’o clock during the day before my exams and my friends in my room will wake up for the whole day.

Sunday, November 7, 2010

Optical Communication question paper with solution for Engineering Students

  1. Define Mode-field diameter.
The fundamental parameter of a single mode fiber is the mode-field diameter. This can be determined from the mode field distribution of the fundamental LP01 mode

  1. What is the necessity of cladding for an optical fiber?
a) To provide proper light guidance inside the core
b) To avoid leakage of light from the fiber
c) To avoid mechanical strength for the fiber
d) To protect the core from scratches and other mechanical losses

  1. Define acceptance angle.
The maximum angle Φmax’ with which a ray of light can enter through the entrance end of the fiber and still be totally internally reflected is called acceptance angle of the fiber

  1. Why do we prefer step index single mode fiber for long distance communication?
Step index single mode fiber has low attenuation due to smaller core diameter & higher bandwidth & very low dispersion.

  1. What are meridional rays & skew rays?
Meridional rays are the rays following Zig Zag  path when they travel through fiber and for every reflection it will cross the fiber axis.
Skew rays are the rays following the helical path around the fiber axis when they travel through the fiber and they would not cross the fiber axis at any time.

  1. What is pulse broadening?
Dispertion induced signal distortion is that a light pulse will broaden as it travels along the fibre.This pulse broadening causes a pulse to overlap with neighbouring pulses.After a time t,the adjacent pulses can no longer be individually distinguished at the receiver and error will occur.

  1. What is polarization Mode Dispersion (PMD)?
The difference in propagation times between the two orthogonal polarization modes will result in pulse spreading.This is called as polarization Mode Dispersion.

Part – B                                              (3x 12 =36)
(Answer any three questions)

  1. What is waveguide dispersion? Derive its expression.

Wave-guide dispersion, which occurs because a single mode fiber confines only 80% of the optical power to the core. Dispersion thus arises since the 20% of the light propagating in the cladding travels faster than the light confined to the core. The amount of wave-guide dispersion depends on the fiber design, since the modal dispersion constant β is a fn of (a / λ)

  1. Explain in detail about various attenuation losses.

v  Absorption Loss:

In optical fibers, the electromagnetic waves are absorbed by the material resulting in increase in attenuation.

Absorption is caused by three different mechanisms in detail with relevant diagram.

·         Absorption by atomic defects in glass composition
·         Extrinsic absorption by impurity atoms in the glass material
·         Intrinsic absorption by the basic constituent atoms of the fiber materials.

v  Scattering Loss:
Scattering losses in glass arise from microscopic variations in the materials density, from compositional fluctuations, and from structural in homogeneities or defects occurring during fiber manufacture.

v  Bending Loss:

Radiative losses occur whenever an optical fiber undergoes a bend of finite radius of curvature. Fibers can be subjected to two types of bends

1.      Macroscopic bends
2.      Microscopic bends

v  Explanation with relevant diagrams

  1.  Briefly explain about Graded index fiber structure & single-mode fiber.

Graded index fiber:
In the graded index fiber design the core refraction index decreases continuously with increasing radial distance ‘r’ from the center of the fiber.
·         Equation
·         Diagram
Single-mode fiber
    Dimensions of core diameter
    Mode-field diameter
Distribution of light in a single-mode fiber above its cutoff wavelength
    Propagation modes i.  Fiber birefringence ii. Fiber beat length