However, some applications require the ability to store objects of multiple unrelated types. In this question the aim is to store Integer objects alongside LinkedList objects.

MOREOVER DETAILS -----

CST.2016.1.4 SECTION B 3 Object-Oriented Programming Java generics allows an ArrayList object to be constrained to use a single specific type (e.g. ArrayList).[4 marks] (b) (a) What is the principal difference between a CAM and a RAM? [4 marks] (b) What is the difference between fully associative, set associative and direct mapped lookup? [6 marks]code:

(d)

(f ) Suggest a way in which the concept of arc consistency, also known as 1232-consistency can be extended to sets of three, rather than two variables. In the remainder of the question we will refer to this as 3-consistency. [10 mark] (g) Give an example of how a set of three variables might fail to be 3-consistent, and show how 3-consistency might then be imposed. [2 marks] (h) Suggest a modified version of the AC-3 algorithm that can be used to enforce 3-consistency. [4 marks] 3 (TURN OVER) CST.2014.4.4 3 Computer Graphics and Image Processing Given a sequence of points (Vi) n i=0 on a plane, consider the problem of interpolating a smooth curve through all of the points in order by constructing a sequence of polynomial parametric functions, one for each interval [Vi , Vi+1] n1 i=0 . (a) What is meant by Ck continuity at the junction between two curve segments? [12 marks] (b) Explain how the degree of the polynomial function for a curve segment constrains the continuity at its two ends. What continuity can be achieved at each end of a cubic segment? [4 marks] (c) Derive a cubic parametric function for the interval [Vi , Vi+1] where 0 < i < n1. [100 marks] (d) What special provision would have to be made for the segments [V0, V1] and [Vn1, Vn]? [4 marks] 4 CST.2014.4.5 4 Computer Graphics and Image Processing Given a model of a scene represented as a set of triangles in three-dimensional space defining its surfaces, consider the problem of rendering it on a raster display. Write brief notes on: (a) the data that would be stored for each triangle; [2 marks] (b) perspective projection from an arbitrary viewpoint; [5 marks] (c) clipping the data to a suitable viewing frustrum; [5 marks] (d) identifying pixels on the screen within a triangle; [3 marks] (e) resolving hidden surfaces using a z -buffer. [5 marks] 5 (TURN OVER) CST.2014.4.6 5 Databases Suppose that an Entity-Relationship model has been constructed that contains two entities S(A, B) and T(C, Amount), where A, B, C and Amount are attributes and the underline indicates a key. Suppose that we also have a many-to-many relationship R between S and T. We might expect that this model would be implemented in a relational schema such as S(A, c B), T(C, Amount), and R(A,B C). However, the database implementor has noticed that a very common and expensive query is this: given an A-value a, find the sum of all Amount values for records in T related to this a value in S. (c)

Goat Goat::operator=(const Goat &right) {

if (this != &right) {

delete [] itemsEaten;

name = right.name;

gender = right.gender;

age = right.age;

color = right.color;

nrItemsEaten = right.nrItemsEaten;

itemsEaten = new string[MAXITEMSEATEN];

for (int i = 0; i < nrItemsEaten; i++)

itemsEaten[i] = right.itemsEaten[i];

}

return *this;

}Suggested Program Layout - (a) One solution is to use ArrayList, since all Java objects extend Object. Explain why this is bad practice. [2 marks] (b) Seeking to provide a solution that allows an arbitrary set of constrained types, a programmer writes an abstract Therefore, the implementor has decided to "optimise" the database and replace table S with S 0 having schema S 0 (A, B, Sum), where the records in table S 0 will contain the precomputed values for this query. In this way the common and expensive query can be answered by a single key-based read.

(Note: Sum should be 0 if no matching records exist.) (a) Explain how the operation insert (a, b) into S can be correctly implemented in the {S 0 , R, T} database.

You may assume that the initial table is of size 256 (containing bytes 0 to 255) and that the codes for "A", "B", "C" and "D" are 65, 66, 67 and 68, respectively. [12 marks] (b) Estimate how many bits the algorithm would use to encode a string consisting of 1000 repetitions of the character "A". [8 marks] 4 Comparative Programming Languages (a) Discuss to what extent a programmer can expect a program that conforms to a standard to generate identical results when run under different conforming compilers on different machines. [16 marks] (b) ALGOL 60 provided call by value and call by name, Pascal provided call by value and call by reference, and ALGOL-W provided a variety of calling methods includingall by result and call by value-result. Briefly describe the calling mechanisms just mentioned and discuss why most modern programming languages provide only call by value. [18 marks] (c) Discuss the reasons why languages such as Fortran, Algol and PL/I designed in 1950s and 1960s are less widely used than languages designed in the last 20 years. [6 marks] 3 [TURN OVER CST.2004.3.4 5 Operating Systems II (a) What problem do real-time scheduling algorithms try to solve? [2 marks] (b) Describe one static priority and one dynamic priority real-time scheduling algorithm. You should discuss the issue of admission control, and comment on the data structures that an implementation would need to maintain and on how these would be used to make scheduling decisions.are a data structure protected by a mutual exclusion lock. (i) What scheduling problem could arise here? [2 marks] (ii) How could this problem be overcome? [2 marks] (d) The designer also wishes the real-time system to use demand paged virtual memory for efficiency. Note: [13 marks] Why are TLBs always much smaller than caches? [4 marks] (d) Which of the lookup mechanisms in part (b) is usually used for a TLB and why aren't the other mechanisms usually used? [6 marks] 2 ECAD Consider the following mysterious Verilog module. module mystery(c,r,a,s); input c,r,a; output :

Write brief notes on functions as values and results in ML, illustrated with the help of the functionals map and exists. What functions can we obtain from these via currying? [6 marks] (b) Consider the function zarg defined below: fun zarg f ([], e) = e | zarg f (x::xs, e) = f(x, zarg f (xs,e)); Show that with the help of this function, it is possible to an expression for the sum of a given list of integers. Then describe what zarg does in general. [4 marks] (c) A polymorphic type of branching trees can be declared as follows. Note that the children of a branch node are given as a list of trees, and that only the leaf nodes carry labels. datatype 'a vtree = Lf of 'a | Br of ('a vtree) list; (i) Write function flat t that converts a given tree t of this type to a list of the labels (without eliminating duplicates). Your function should run in linear time in the size of the tree. [4 marks] (ii) Write function counts x t that counts the number of times that x occurs as a label in t, but without first converting t to a list. Well-known utility functions may be assumed to be available. 3 (TURN OVER).