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Wednesday, 22 June 2016

High Speed Networks and Internets-Model Question Paper



1(a) List the major advantages with layered approach to protocols. (5 Marks)
(b) Describe some circumstances where it might be desirable to use source routing rather than let the routers make the routing decision. (4 marks)
(c) Compare the individual fields of the IPv4 header with the IPv6 header. Account for the functionality provided by each IPv4 field by showing how the same functionality is provided in IPv6. (8 Marks)
(d) There is no error detection mechanism (frame check sequence) in X.25. Isn’t this needed to assure that all of the packets are delivered properly? (3 Marks)
2(a) List all possible values of the GFC and the interpretation of each value. (8 Marks)
(b) Write a note on the emergence of High-Speed LANs. (4 Marks)
(c) Mention five applications of fiber channel. (5 Marks)
(d) Write a short note on service area requirement for a wireless LAN. (3 Marks)
3(a) Show that, all other things being equal, the greater the correlation coefficient of two random variables, the greater the variance of their sum and the less the variance of their difference. (6 Marks)
(b) The owner of a shop observes that on average 18 customers per hour arrive and there are typically 8 customers in the shop. What is the average length of time each customer spends in the shop? (4 Marks)
(c) Consider a single queue with a constant service time of 4 seconds and a poisson input with mean rate of 0.20 items per second. Find the mean and standard deviation of (i) queue size and (ii) residence time. (6 Marks)
(d)Show that the Cantor set consists of all points in the interval [0,1] that have no 1’s in their base-3 expression. (4 Marks)
4(a) Write a note on effects of congestion. (6 Marks)
(b) Explain the terms committed burst size and excess burst size. (6 Marks)
(c) A channel has a data rate of 4 kbps and a propagation delay of 20 ms. For what range of frame sizes does stop and wait give an efficiency of at least 50%? (4 Marks)
(d) A TCP entity opens a connection and uses slow start. Approximately how many round trip timers are required before TCP can send N segments? (4 Marks)
5 (a) Write a note on cell delay variation in ATM network. (4 Marks)
(b) Explain three ATM QoS parameters defined by the ATM forum. (6 Marks)
(c) The graph Kn, called the complete graph of n vertices, has n vertices and every vertex is joined to every other vertex by an edge. Find a formula for the number of edges in Kn. (6 Marks)
(d) Will Dijkstra’s algorithm and the Bellman-Ford algorithm always yield the same solutions? Explain. (4 Marks)
6(a) When multiple equal cost routes to a destination exist, OSPF may distribute traffic equally among the routes. This is called load balancing. What effect does such load balancing have on a transport layer protocol, such as TCP? (4 Marks)
(b) Assume a router has 30 routes to advertise using RIP, requiring one datagram with 25 routes and another with the remaining 5. What happens if once an hour the first datagram with 25 routes is lost? (4 Marks)
(c) IGMP specifies that query messages are sent in IP datagrams that have the Time to Live field set to 1. Why? (4 Marks)
(d) Explain in detail why MOSPF would be inefficient in a sparse multicast environment. (8 Marks)
7(a) What is Bit-Round Fair Queuing (BRFQ)? (4 Marks)
(b) Illustrate how the last two fields in RTCP SR or RR receiver report block can be used to calculate round-trip propagation time. (8 Marks)
(c) In RSVP, because the UDP/TCP port numbers are used for packet classification, each router must be able to examine these fields. This requirement raises problems in the following areas: (i) IPv4 header processing and (ii) IP-level security. Indicate the nature of the problem in each area, and suggest a solution. (8 Marks)
8 (a) Write a note on characteristics of the Huffman code. (6 Marks)
(b) How can the BWT algorithm improve compression performance? (4 Marks)
(c) JPEG has defined four modes of operation. Explain. (4 Marks)
(d) In a straight forward implementation of LZ77 coding, which step would be faster, compression or decompression.? Why? (6 Marks)

Thursday, 16 July 2015

Parallel Computing-Model question paper for B.E/B.Tech Computer Science Engineering



1(a) Why do you think that parallel processing with large number of nodes has been still in infancy as far as general purpose computing is concerned? (4 Marks)
(b) Give two reasons why Amdahl’s law should hold? Is it possible that there are cases where the law may fail? If yes, explain. (6 Marks)
(c) Do you find any machine that does not fit into Shore’s classification scheme? Explain. (6 Marks)
(d) A processor had no floating point unit in earlier version but was added to it later. The speedup for floating point operations is 500 compared to software implementation of floating point routines. Find the speedup for programs that has floating point operations in the original machine consuming 10%, 20% and 90% of time. (4 Marks)
2(a) Using a neat sketch explain electronic implementation of a pipeline. (6 Marks)
(b) Write a note on optimal pipe segmentation. (6 marks)
(c) Distinguish between fixed point addition pipeline and floating point add pipeline using neat sketches. (8 Marks)
3(a) Control of a pipeline instruction processor poses a number of problems. Explain. (6 Marks)
(b) Using a neat figure, explain the instruction processing pipeline in superscalar processor. (8 Marks)
(c)Given 3-stage multiplier pipe and 2-stage adder pipe and delays, draw a schematic of a chained pipeline for doing the following vector computation on vectors A,B,C and Y. Yi=(Ai-2 + Bi)*Ci-3 + Di+1 (6 Marks)
4(a) Give the schematic design of a scheduler that implements following latency cycle for dynamically configured pipe running for operations A, B, C and D. Give the number of initiations per clock (IPC). Latency cycle = <2AD 3ABC 1BD 2AC> (8 Marks)
(b) Write a note on static branch prediction. (4 Marks)
(c) Prove that the average latency of any greedy cycle (simple) is less than or equal to the number of 1’s in the collision vector (d0 is included) of the reservation table. (8 Marks)
5(a) Work out an algorithm to multiply two 4x4 matrices on a hypercube machine having 16 nodes. (6 Marks)
(b) A data item is to be distributed to all the PEs. Find out the data routing steps to carry out the job for hypercube connected machine. (6 Marks)
(c) A ring connected SIMD parallel computer is to add n numbers. Work out a parallel algorithm to add these n-node rings. How many routing steps will be required? What is the time complexity to perform the n number addition on n-node ring machine? (8 Marks)
6(a) Write a note on ILLIAC IV Computer. (4 Marks)
(b) Draw and explain different communication ports of PE in a mesh connected computer. (4 Marks)
(c) Assume a 64 node mesh connected machine having the 64 records of 64 students. It is desired to find all students having more than 90% marks. Work out the program schematic for the problem. What is the speedup obtained? (6 Marks)
(d) A two dimensional matrix of 8x8 contains real numbers. It stands for the values of pixels of same image. A simple smoothing algorithm requires to smoothen out the image so that every element of the matrix is replaced by the average value of the four neighbors. Formulate the parallel algorithm and code it for the machine discussed. (6 Marks)
7(a) Illustrate the data routing from node 6 to 14 in a single stage shuffle exchange network. (6 Marks)
(b) How many steps shall be required for routing a data item from one node to another in a 32 node Omega network. Explain. (4 Marks)
(c) Illustrate the routing algorithm for the 8x8 Benes network with permutation p = [1  3  5  7  6  8  9  0  4  2  11  10] (6 Marks)
(d) Design an 8x8 cross bar using digital logic elements. (4 Marks)
8(a) What is the effect of low and high value of τ on SLT network? (4 Marks)
(b) Can 2 input XORs be implemented using 3 neurons? If yes, show the neural network with its weights. (6 Marks)
(c) Take a 3 PML node 2 input 3 class neural network and illustrate the training algorithm for classification for 2 classes. (6 Marks)
(d) State and explain Hebb’s learning (Delta rule). (4 Marks)

Tuesday, 7 July 2015

Mechanics of Materials- Model question paper for B.E/B.Tech Mechanical engineering



1(a) State St.Venant’s principle. (4 Marks)
(b) Write a brief note on properties of engineering materials.(6 Marks)
(c) Deduce a relation between Young’s modulus and Rigidity modulus. (6 Marks)
(d) A steel press has four tension members. Each member has a diameter of 16 mm. The largest load to be resisted by the press is to be 48 kN. Determine axial stress in the tension members. (4 Marks)
2(a) Prove that normal stress acting on maximum and minimum shear stress planes is the average of any two orthogonal normal stresses acting on the point. (8 Marks)
(b) Write a note on construction of Mohr’s circle. (8 Marks)
(c) A round bar of 30mm diameter is subjected to an axial compressive force P. Taking the allowable stresses for the material of the bar as 110 MPa in compression and 50 MPa in shear, determine the magnitude of maximum value of P which can be applied such that the member does not fail. (4 Marks)
3(a) The magnitude of bending moment at a section will be maximum or minimum when the shear force at that section is zero or changes its sign. Explain. (8 Marks)
(b) A 6m long beam simply supported its ends is subjected to UDL of 30 kN/m over 2 meters length from LHS support. Draw the SF and BM diagrams. (8 Marks)
(c) A 6 meters long beam is simply supported such that there is a over hang of L meters on either support. The beam is subjected to load W at its either ends. Determine W and L such that maximum bending moment and maximum shear stress induced in the beam are 30 kN-m and 15 kN respectively. (4 Marks)
4(a) What are the assumptions made during the derivation of equations related to theory of pure bending. (6 Marks)
(b) What is section modulus? Find the section modulus of a hollow circle. (6 Marks)
(c) A beam with I section has two equal flanges of each 220 mm wide and 12 mm thick. The web has 12 mm thickness and depth 460 mm. Determine the percentage of moment of resistance shared by the flanges and web, when the section is subjected to bending moment M. (8 Marks)
5(a) Derive the moment-curvature relationship for the deflected curve. (8 Marks)
(b) Macauleys method is an improved version of double integration method which can be used for finding the deflections of beams subjected to discontinuous loads. Explain. (8 Marks)
(c) A 2 meters long cantilever is subjected to UDL of 10 kN/m throughout its length and a vertically downward point load 20 kN at its free end. Taking E=200 GPa and maximum deflection as 0.3 mm, determine the width and depth of rectangular section. Depth of the section is twice the width. (4 Marks)
6(a) Show that shear stress distribution in any section of a shaft is directly proportional to the torque applied. (5 Marks)
(b) Explain the terms torsional rigidity and torsional flexibility. (6 Marks)
(c) Compare the mass of solid shaft with that of hollow shaft of same length, when they are made of same material and are to transmit same power at same speed. The outer diameter of hollow shaft is 1.4 times its inner diameter. Maximum shear stresses induced in both cases are equal. (5 Marks)
(d) A 1m long wire is hung in vertical position and disc is attatched at the bottom end. Diameter of the wire is 2 mm. Material of wire has yield stress in shear of 150 MPa. Determine the angle through which the disc can be rotated so that the wire does not yield. Take G= 80 GPa. (4 Marks)
7(a) Develop Euler’s buckling load formula for the column with both ends hinged. (6 Marks)
(b) Write a note on limitations of Euler’s formula. (4 Marks)
(c) Derive Rankine-Gordon formula. (6 Marks)
(d) A column 2.6 meters long with a square section of side 50 mm is to be replaced by a column with hollow square section of outer side 70 mm. Determine the wall thickness of the column and percentage saving in material. Both ends of the column are hinged. (4 Marks)
8(a) Show that the volumetric strain is the sum of longitudinal strain and twice the circumferential strain. (6 Marks)
(b) Radial and circumferential stresses in a thick wall pressure vessel vary parabolically across the section of the wall, while longitudinal stress is uniform throughout the cylinder. Explain. (6 Marks)
(c) A pressure vessel with outer and inner diameters of 400 mm and 320 mm respectively is subjected to an external pressure 8 MPa. Determine the circumferential stress induced at the inner and outer surfaces. (4 Marks)
(d) A water pipe with 500 mm diameter supplies water at 51 meters head. Taking allowable stress for pipe material as 30 MPa and efficiency of circumferential riveted joint as 80%, determine the thickness of the pipe. Specific weight of water is 9.81 kN/m3. (4 Marks)

Field theory-Model question paper for B.E/B.Tech



1(a)  A uniform volume charge distribution exists in a spherical volume of radius a. Using the concept of  energy density or otherwise, find the total energy of the system.  (6 Marks)
(b) Three charges -1(µC), 4(µC) and 3(µC) are located in free space at (0,0,0), (0,0,1) and (1,0,0) respectively. Find the energy stored in the system. (4 Marks)
(c) Transform the vector A = y ax – x ay + z az into cylindrical co-ordinates. (4 Marks)
(d) The electric potential in the vicinity of the origin is given as V = 10x2 + 20 y2 + 5 z2 (V). What is the electric field intensity? Can this potential function exist? (6 Marks)
2(a) Determine the capacitance of a parallel-plate capacitor consisting of  two parallel conducting plates of area A and separation d. (6 Marks)
(b) Using Laplace’s equation, obtain the potential distribution between two spherical conductors separated by a single dielectric. The inner spherical conductor of radius ‘a’ is at a potential ‘V0’ and the outer conductor of radius ‘b’ is at potential 0. Also find variation of E. (8 Marks)
(c) A cubical region of space is defined by the surfaces x=1.8, y=1.8, z=1.8,x=2, y=2 and z=2. If D=3y2ax+3x2yax (C/m2);
(i) Find the exact value of the total charge enclosed within the cube by surface integration.
(ii) Find an appropriate value for the enclosed charge by evaluation of derivatives at the centre of the cube.  (6 Marks)
3(a) State Ampere’s circuital law. (4 Marks)
(b) State Stoke’s theorem. (4 Marks)
(c) Show that the magnetic flux density B set up by an infinitely long current-carrying conductor satisfies the Gauss’s law. (4 Marks)
(d) A cylinder of radius ‘b’ and length ‘L’ is closely and tightly wound with N turns of a very fine conducting wire. If the wire carries a dc current I, find the magnetic flux density at any point on the axis of the cylinder (solenoid). What is the magnetic flux density at the centre of the cylinder? Also, find B at the ends of the cylinder. (8 Marks)
4(a) Write a note on magnetic torque and moment on a closed circuit. (6 Marks)
(b) What are magnetic circuits? Distinguish between linear and non-linear magnetic circuits. (10 Marks)
(c) Through a suitable experiment on a magnetic material, the magnetic flux density B is found to be 1.2 T when H=300 A/m. When H is increased to 1500 A/m, the B field increased to 1.5 T. What is the percentage change in the magnetization vector? (4 Marks)
5(a) Find the self-inductance per unit length of an infinitely long solenoid. (6 Marks)
(b) A steady state current is restricted to flow on the outer surface of the inner conductor (ρ=a) and the inner surface of the outer conductor (ρ=b) in a coaxial cable. If the coaxial cable carries a current I, determine the energy stored per unit length in the magnetic field in the region between the two conductors. Assume that the dielectric is non-magnetic. (8 Marks)
(c)  Consider two coupled circuits having self-inductances L1 and L2 that carry currents I1 and I2 respectively. The mutual inductance between the two coupled circuits is M12. Find the ratio I1/I2 that makes the stored magnetic energy Wm a minimum. (6 Marks)
6(a) State Faraday’s law. Derive Maxwell’s equation in point form from faraday’s law. (8 Marks)
(b) Show that for a sinusoidally varying field, the conduction current and the displacement current are always displaced by 900 in phase. (4 Marks)
(c) The dry earth has a conductivity 10-8 S/m, and a relative permittivity 4. Find the frequency range on which the conduction current dominates the displacement current. (4 Marks)
(d) Write Maxwell’s equations in integral form. (4 Marks)
7(a) Derive the differential form of continuity equation from the Maxwell’s equations. (4 Marks)
(b) Write the set of four Maxwell’s equations in terms of eight scalar equations in Cartesian coordinates. (12 Marks)
(c) Consider the wet earth with the following properties: ε = 30 ε0 μ = μ0  σ = 10-2 S/m. Determine the ratio of amplitudes of conduction and displacement currents at 100 MHz. (4 Marks)
8(a) Write the phasor and time-domain forms of a uniform plane wave having a frequency of 1 GHz, that is traveling in the +x=direction in a medium of ε = 12ε0
μ = μ0. ( 6 Marks)
(b) Define skin depth. Prove that high frequency resistance is very much greater than dc resistance. (6 Marks)
(c) State and explain Poynting’s theorem. (5 Marks)
(d) Determine the critical angle if the refractive index of the medium is 1.77. (3 Marks)